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. 2020 Aug 17;15(8):e0237318. doi: 10.1371/journal.pone.0237318

Field evaluation of sunflower as a potential trap crop of Lygus pratensis in cotton fields

Renfu Zhang 1,2, Wei Wang 2, Haiyang Liu 2, Dengyuan Wang 1,*, Ju Yao 2,*
Editor: Yonggen Lou3
PMCID: PMC7430709  PMID: 32804952

Abstract

The mirid bug Lygus pratensis is an important pest of cotton, and is primarily managed through insecticide application. In this study, conducted in Xinjiang (China), we assessed the relative attractiveness of sunflower (Helianthus annuus) to L. pratensis adults in local cotton plots from 2015–2016 and quantified the associated contribution of inter-planted sunflower strips to suppress field-level L. pratensis populations from 2016–2017. Field-plot trials showed that among six combinations of two sunflower varieties (XKZ6 and SH363) and three planting dates (early-, middle- and late-planted), adult abundance of L. pratensis was highest on early-planted XKZ6 and attained 3.7–5.8 times higher levels than in neighboring cotton plots. In commercial cotton fields, the combined deployment of sunflower strips at field edges and the periodic application of insecticides directed to those strips was found to (1) reduce the mean abundance of L. pratensis population on cotton by 41.9–44.0%, (2) lower the rate of cotton leaf damage by 27.3–30.6% and boll damage by 44.8–46.0%, and (3) increase the number of mature bolls by 7.5%-8.0%. Our work emphasizes how sunflower can be an effective trap crop for L. pratensis and that the establishment of sunflower strips could contribute to its effective and environmentally-sound management in cotton crops.

Introduction

Lygus pratensis (L.) (Hemiptera: Miridae) is a common pest on cotton (Gossypium spp.), alfalfa (Medicago sativa), Chinese date (Ziziphus jujuba), grape (Vitis vinifera), pear (Pyrus spp.), apple (Malus pumila) and many other crops. Aside from its broad host range, this mirid bug has a wide geographic distribution and is found throughout Europe, north Africa, the Middle East, northern India, China, and Siberia [1,2]. In China, L. pratensis is found mainly in the Xinjiang Uyghur Autonomous Region, and was locally regarded as a major pest on cotton in the 1950s and 1960s [3–5]. Both nymphs and adults of L. pratensis feed on vegetative and reproductive parts of cotton plants, thus causing leaf damage, plant stunting and abscission of squares and bolls [6–9]. Occasionally, L. pratensis outbreaks caused 100% damage to cotton plants and resulted in significant loss of crop quality and yield [10]. Over the past decades, insecticide-based approaches have suppressed L. pratensis population levels and safeguarded cotton yields [9]. Yet, L. pratensis population levels in Xinjiang have increased in recent years after wide-scale adoption of Bt (Bacillus thuringiensis) cotton, and this mirid bug has now re-emerged as a major pest of cotton and multiple other crops (e.g., stone fruits) in cotton agro-landscapes [1,11–14]. As chemically-synthesized insecticides continue to be the cornerstone of L. pratensis mitigation programs [1,14], non-chemical technologies need to be developed, validated and implemented [15].

As a polyphagous pest, L. pratensis disperses from one host plant to another under field conditions, and exhibits variable feeding responses and a marked preference for plants at flowering stage [16,17]. This type of foraging behavior lends itself to devise trap cropping systems; a method of behavioral manipulation based on the pest’s host plant preferences [18,19]. By establishing the pest’s preferred host plant (i.e., trap plant) close to the main crop, the target pest is diverted from the main crop and pest damage is lowered. Trap cropping been successfully used against multiple economically-important pests, and been successfully applied for the management of many important pests, including several species of mirid bugs (Hemiptera: Miridae) [20]. For instance, the cotton-alfalfa trap crop system relies on alfalfa strips sown within cotton fields to control Lygus hesperus Knight in the United States [21–23]. A similar intercropping pattern has been used in Australia to lower infestation levels of Creontiades dilutus (Stål) in Australia [24]. Alfalfa has also been used as a trap crop for several species of Lygus (e.g., L. hesperus and L. rugulipennis Poppius) in strawberry (Fragaria ananassa) fields in the United States and in Italy [25–27]. In the UK, German chamomile, Matricaria recutita, acts as a trap crop for L. rugulipennis on strawberry [28] Furthermore, other plant species, such as red clover (Trifolium pretense), mugwort (Artemisia vulgaris) and sunflower (Helianthus annuus), can be used for trapping species of Lygus spp. in lettuce (Lactuca sativa) and cucumber (Cucumis sativus) [29,30]. In Chinese cotton fields, mungbean (Vigna radiata) and cowpea (Vigna unguiculata) are used as trap crops for Apolygus lucorum (Meyer-Dür) and Adelphocoris suturalis (Jakovlev), respectively [31,32]. Overall, trap cropping has proven to be an effective means of mirid bug management in various agro-ecosystems worldwide and thus carries ample promise to reduce the current reliance upon chemically-synthesized insecticides to control L. pratensis.

In our field survey, L. pratensis was found to attain high population levels on sunflower, hinting its potential value as a trap crop for this mirid bug. In this study, we 1) compared L. pratensis infestation levels in field plots established with cotton and different varieties and planting dates of sunflower, 2) assessed whether L. pratensis’ infestation pressure and damage was lowered in cotton fields inter-planted with sunflower strips.

Materials and methods

Plants and field sites

In our trials, we used two sunflower varieties: (1) XKZ6, bred by Institute of Crop Research, Xinjiang Academy of Agricultural Reclamation Sciences (Xinjiang, China) and (2) SH363 bred by Gansu Derui Agricultural Science and Technology Co., Ltd. (Gansu Province, China). The cotton variety used was ZM49, bred by the Institute of Cotton Research, Chinese Academy of Agricultural Science (Henan Province, China). All field experiments were conducted in Guzai village (E77º26′92″, N38º55′14″), Tagaerqi township, Shache County in Xinjiang, China.

Lygus pratensis occurrence in cotton and sunflower plots

In 2015, cotton was planted on April 1, and sunflower was sown at three different times: April 1 (early-planted), April 10 (middle-planted), and April 20 (late-planted). In 2016, cotton was sown on April 3, and sunflower was sown on April 3 (early-planted), April 13 (middle-planted), and April 23 (late-planted). During each year, the following treatments were established: two sunflower varieties (i.e., XKZ6, SH363) each with three planting dates (6 treatments), and cotton with a single planting date (control treatment).

Each of the above treatments was established in 3 field plots (i.e., replicates), totaling 21 plots for the entire experiment. Each plot was 100 m2 (i.e., 10 m wide by 10 m long), and all plots were randomly arranged with 2 m wide vegetation-free aisles between neighboring plots. The seeding density was 2.25×105 seeds per ha for cotton, and 6.5×104 seeds per ha for sunflower. All plots were under flood irrigation with an identical fertilization and watering regime, and no chemical pesticides were applied during the entire growing season. A field survey of L. pratensis population was conducted every five days from early June to middle August during both years. In each plot, using five-point sampling method and 20 consecutive plants were checked each point (Fig 1A), the number of L. pratensis adults was visually determined and recorded.

Fig 1. The population investigate method of Lygus pratensis in field.

Fig 1

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(a) The left picture showed the investigation method of sunflower with different varieties and planting dates, and cotton in the plots. Within green square represent plot, and red indicates sampling points. b) The right picture showed the investigation method in cotton field with and without sunflower strips. Yellow lines are sunflower strips, and red indicates sampling points.

Beginning in early June, as these first generation of L pratensis nymphs become adults on spring host plants, they disperse to other host plants and then produce second generation there. In other words, before they attack the sunflower and cottons, no L. pratensis’ infestation were occurred on these two crops. Therefore, we only investigate the relative attractiveness of sunflowers and cottons to adults from entering period, ignore the nymphs.

Lygus pratensis occurrence in cotton with and without sunflower border strips

Cotton and sunflower were simultaneously planted on April 5, 2016 and April 9, 2017. Seeding densities of cotton and sunflower were 2.25×105 seeds per ha and 6.5×104 seeds per ha, respectively. During each year, a total of eight cotton fields (each approximately 30 m wide and 30 m long) were set up with >10 m wide vegetation-free areas between neighboring fields. Four cotton fields with sunflower strips were established as trap cropping treatments, and the other four without sunflower strips were designated as control treatment.

For each trap-cropping field, two 1-m wide strips of sunflower (accounting for 6% crop surface) were planted on the opposite borders of the field, parallel to the cotton rows. Cotton fields with and without sunflower strips were managed under identical irrigation, fertilization and crop management schemes. No pesticides were used on cotton plants in any of the fields. To control L. pratensis populations on sunflower strips, 40% acetamiprid water dispersible granules at 120g/ha or 25% imidacloprid wettable powder at 120g/ha with water 600 kg/ha were applied in alternation every 10 days following the first detection of the pest.

Sampling of L. pratensis in cotton fields was done every five days, from early June to mid-August, using the same method as above. On each sampling date, the number of L. pratensis adults and nymphs (per plant) was recorded, and L. pratensis feeding damage on the top five cotton leaves was assessed in late June. Also, the number of mature cotton bolls (diameter >2.5 cm) was determined and the damage rate for bolls was determined in late August. For both boll number and damage level, 100 plants from five selected points (20 plants per point) were examined in each field (Fig 1B).

Statistical analysis

Differences in the abundance of L. pratensis (including adults, nymphs, and total population, as three counts) in cotton and sunflower plots (2015–2016) or in cotton fields with/without sunflower strips (2016–2017) were analyzed by a repeated-measures analysis of variance (ANOVA) using SAS PROC MIXED, and the means were compared by the least significant difference test (LSD). The data were log10(n+1)-transformed before analysis. The mean abundances of L. pratensis adults in plots of cotton and sunflower during 2015–2016 were compared using one-way ANOVA followed by Tukey’s HSD for multiple comparisons. Mean abundances of L. pratensis population, the damage rate of leaves and bolls (arcsin-transformed), and the number of mature bolls in cotton fields with/without sunflower strips during 2016–2017 were compared through non-paired t-tests. In 2016 and 2017, L. pratensis abundances in both cotton fields were below the existing economic thresholds for this pest (i.e., 20 bugs per 100 cotton plants at blossoming stage; Wang et al. [14]) after middle July. Hence, only population abundance records from early June to mid-July were included in the repeated-measures ANOVA and non-paired t-tests.

Results

Lygus pratensis occurrence in cotton and sunflower plots

In 2015 and 2016, L. pratensis adults attained peak abundance between early June and late July in cotton fields. In June, adult abundance was high on early-planted sunflower while in July, abundance of L. pratensis adults was relatively higher on early- and middle-planted sunflower. In plots of late-planted sunflower, adult abundance remained low throughout the whole period (Figs 2 and 3).

Fig 2.

Fig 2

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Population dynamics of Lygus pratensis adults on field plots-established with cotton and sunflower with different planting dates in 2015 (a) and 2016 (b). ZM49 is cotton, XKZ6 and SH363 are sunflower varieties. The same as below.

Fig 3.

Fig 3

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Mean population abundances of Lygus pratensis adults on field plots-established with cotton and sunflower with different planting dates in 2015 (a) and 2016 (b).

Population levels of L. pratensis adults differed significantly among all seven treatments in 2015 (repeated measures ANOVA; F(6,12) = 70.88, P <0.0001) and 2016 (F(6,12) = 43.59, P <0.0001) (Fig 2). Also, mean abundance of L. pratensis adults on early-planted XKZ6 was significantly higher than on the other six treatments during both years (one-way ANOVA; 2015: F(6,12) = 66.37, P <0.0001; and 2016: F(6,12) = 107.58, P <0.0001). More specifically, adult abundance on early-planted XKZ6 was 3.73 times and 5.81 times higher than that on cotton in 2015 and 2016, respectively (Fig 3). Cotton as control treatment, early-plant sunflowers XKZ6 have the highest attraction for L. pratensis, so it have more potential as trap crop in cotton fields. Therefore, comparing the abundance of L. pratensis between sunflowers and cotton is requisite and meaningful.

Lygus pratensis occurrence in cotton with and without sunflower strips

As results above showed, early-plant sunflowers have more attractiveness to L. pratensis adults, so used early-plant sunflower strips in cotton fields as trap crop. Because L. pratensis adults produced second and three generations in cotton fields, to assess the role of sunflower strips on population dynamics of L. pratensis in cotton fields, the abundance including adults and nymphs were investigated.

As compared with control treatments, L. pratensis population levels were markedly lower in cotton fields with sunflower borders during 2016 and 2017 (Fig 4). More specifically, significant differences were recorded between fields with and without sunflower strips for population levels of L. pratensis nymphs (repeated measures ANOVA; F(1,3) = 11.44, P = 0.0430) and all individuals (nymphs and adults; F(1,3) = 23.52, P = 0.0167) in 2016. In 2017, significant differences were recorded for adults (F(1,3) = 21.36, P = 0.0191), nymphs (F(1,3) = 10.46, P = 0.0481) and all individuals (F(1,3) = 34.87, P = 0.0097) in 2017. During both years, population abundances of adults, nymphs and all individuals significantly varied between different sampling periods, and the interactions between trap cropping treatment and sampling period also were significantly for mirid bug abundances (except the adult in 2016; F(8,48) = 0.63, P = 0.7504) (Table 1).

Fig 4.

Fig 4

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Population dynamics of Lygus pratensis adults and nymphs in cotton fields with and without sunflower strips in 2016 (a) and 2017 (b). Population dynamics of Lygus pratensis adults and nymphs are both in cotton fields which with and without sunflower strip.

Table 1. Mixed effect linear model (MIXED) analysis of population abundance of Lygus pratensis in cotton fields with and without sunflower strips, during 2016 and 2017.

Year Development stage Effect Ndf Ddf F P
2016 Adults Trap cropping treatment 1 3 8.44 0.0622
Sampling period 8 48 46.41 <0.0001
Trap cropping treatment * Sampling period 8 48 0.63 0.7504
Nymphs Trap cropping treatment 1 3 11.44 0.0430
Sampling period 8 48 339.89 <0.0001
Trap cropping treatment * Sampling period 8 48 5.47 <0.0001
Adults and nymphs Trap cropping treatment 1 3 23.52 0.0167
Sampling period 8 48 47.80 <0.0001
Trap cropping treatment * Sampling period 8 48 4.71 0.0003
2017 Adults Trap cropping treatment 1 3 21.36 0.0191
Sampling period 8 48 45.39 <0.0001
Trap cropping treatment * Sampling period 8 48 2.92 0.0098
Nymphs Trap cropping treatment 1 3 10.46 0.0481
Sampling period 8 48 307.63 <0.0001
Trap cropping treatment * Sampling period 8 48 3.93 0.0012
Adults and nymphs Trap cropping treatment 1 3 34.87 0.0097
Sampling period 8 48 25.20 <0.0001
Trap cropping treatment * Sampling period 8 48 4.35 0.0005
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In both years, cotton fields with sunflower strips had significant reductions in the mean abundance of adults (non-paired t-tests; 2016: t = 6.75, df = 6, P = 0.0005; and 2017: t = 4.78, df = 6, P = 0.0031), nymphs (2016: t = 7.48, df = 6, P = 0.0003; and 2017: t = 4.03, df = 6, P = 0.0069), and all individuals (2016: t = 8.78, df = 6, P = 0.0001; and 2017: t = 5.83, df = 6, P = 0.0011). Also, significant reductions were recorded in the rate of leaf damage (2016: t = 3.35, df = 6, P = 0.0154; and 2017: t = 3.93, df = 6, P = 0.0077), boll damage (2016: t = 7.26, df = 6, P = 0.0003; and 2017: t = 7.24, df = 6, P = 0.0004), while the number of bolls was significantly higher (2016: t = 2.94, df = 6, P = 0.0259; and 2017: t = 2.47, df = 6, P = 0.0484) in the cotton fields with sunflower strips. More specifically, as compared with control treatments, L. pratensis abundance decreased by 41.9% and 44.0% in the trap-cropped fields during 2016 and 2017, respectively. Moreover, respective rates of leaf damage and boll damage decreased by 27.3% and 44.8% in 2016, and by 30.6% and 46.0% in 2017. The number of bolls was 8.0% and 7.5% higher in trap-cropped fields during 2016 and 2017, respectively (Table 2).

Table 2. Abundance and damage of Lygus pratensis to cotton plants in fields with and without sunflower strips, during 2016 and 2017.

Year Abundance and damage Cotton fields Statistic results
With sunflower strip Without sunflower strip t df P
2016 Mean number of adults per 100 plants 8.10±0.11 10.85±0.39 6.75 6 0.0005
Mean number of nymphs per 100 plants 13.98±0.42 27.10±1.70 7.48 6 0.0003
Mean number of adults and nymphs per 100 plants 22.08±0.32 37.98±1.78 8.78 6 0.0001
Rate of leaf damage (%) 9.60±0.43 13.20±0.98 3.35 6 0.0154
Number of bolls per 100 plants 355.50±5.84 329.25±6.75 2.94 6 0.0259
Rate of boll damage (%) 22.63±1.81 40.99±1.75 7.26 6 0.0003
2017 Mean number of adults per 100 plants 10.38±0.69 15.20±0.74 4.78 6 0.0031
Mean number of nymphs per 100 plants 16.15±1.09 32.20±3.83 4.03 6 0.0069
Mean number of adults and nymphs per 100 plants 26.53±1.53 47.40±3.24 5.83 6 0.0011
Rate of leaf damage (%) 10.45±0.84 15.05±0.81 3.93 6 0.0077
Number of bolls per 100 plants 348.50±7.31 324.25±6.55 2.47 6 0.0484
Rate of boll damage (%) 24.60±1.33 45.54±2.48 7.24 6 0.0004
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Statistical comparisons refer to data within a row.

Discussion

The mirid bug Lygus pratensis is a polyphagous, economically-important pest of multiple crops in Europe, central Asia and north Africa, and is a common target of insecticide applications in cotton fields in China. In this study, we revealed how L. pratensis adults greatly preferred sunflower plants sown in early season, and showed how sunflower strips clearly suppressed L. pratensis population levels and crop damage in cotton. Our work can constitute the basis for further development of integrated pest management schemes against L. pratensis in China’s cotton crop, and eventually permit significant reductions in insecticide use against this pest.

Aside from its role in lowering L. pratensis population levels in China’s cotton crop, sunflower has also shown potential as a trap crop in various other crop x pest systems e.g., for control of the stalk borer Dectes texanus LeConte (Coleoptera: Cerambycidae) in soybean [33], the brown marmorated stink bug, Halyomorpha halys Stål (Hemiptera: Pentatomidae), in pepper [34,35], and the European tarnished plant bug, L. rugulipennis, in glasshouse cucumber [30]. Also, multi-species strips of sunflower, Chinese cabbage, marigolds and rapes can help suppress the pollen beetle, Melighetes aeneus F. (Coleoptera: Nitidulidae), in cauliflower fields [36]. Hence, considering the importance of L. pratensis as a key pest of alfalfa, vegetables, fruit trees, and multiple other crops [1], sunflower strips potentially could also serve as a trap crop and help alleviate insecticide application pressure in these other crops.

The success of trap cropping depends upon the presence of a highly-attractive trap crop, during times when the population of the target pest is high [18]. Hence, the spatio-temporal presence of a trap crop (e.g., planting date, growth dynamics and flowering time) is an important selection criterion when devising a trap-cropping strategy aimed at a particular pest [20]. In certain cases, the target pest can sustain high population levels during prolonged periods of time, and a staggered establishment of a trap crop might thus be needed to sustain its attractiveness [31,37,38]. In our study, the 2015–2016 survey showed comparatively high L. pratensis adult infestation levels in cotton fields during June, which were similar to those in plots with early-planted sunflower. The attractiveness of early-planted sunflower also appeared to be superior to that of middle- and late-planted ones, further accentuating its potential as a trap crop for L. pratensis in local cotton agro-ecosystems.

As considerable intra-specific variability may occur in the degree of attractiveness of a particular trap crop to a given pest [39,40], field work is often required to carefully select the most attractive varieties. Furthermore, yield and marketability of a given trap crop variety could also be determining factors in securing its wider adoption by farmers [41]. This study compared two common varieties of sunflower and revealed the superior attractiveness of early-planted XKZ6. Yet, no intra-specific differences in in-field L. pratensis attraction were reported for middle- and late-planted sunflower, possibly related to particularities of L. pratensis adult host plant selection and its marked preference for plants at the budding and blossoming stage [1,16]. Early-planted sunflower generally entered into bud stage by late May, at which time high L. pratensis adult abundance was recorded in the field. Also, XKZ6 is characterized by a comparatively slower development from bud to florescence, which might have further enhanced its attractiveness to L. pratensis over the course of June.

Periodic suppression of target pests within the trap-crop strips can reduce the potential of re-colonization of the main crop and boost its pest control efficiency [18]. In our study, insecticide sprays in sunflower strips at a 10-day frequency significantly lowered L. pratensis abundance in the neighboring cotton field. As sunflower strips solely occupied 6% of the cotton area, the current 6 insecticide sprays directed to the trap-crop strips amounted to a mere 0.36 applications in terms of total cotton area. Thus, trap cropping might greatly reduce the amount of chemical insecticides for L. pratensis control in cotton and lower the environmental burden of commercial cotton production in Xinjiang, China.

Sunflower is an important crop in its own right in southern Xinjiang, and socio-economic factors possibly can further facilitate its field-level establishment by local cotton growers. Yet, given the proven environmental impacts of neonicotinoid insecticides such as acetamiprid and imidacloprid [42], and the unmistakable risks those products pose to pollinators, insect natural enemies and other wildlife, future studies should investigate biopesticides and more environmentally-friendly alternatives for L. pratensis control. A number of other control options of L. pratensis, including the use of sex pheromones and light traps [1], have the potential to be coupled with trap cropping and might further boost control efficacy of sunflower strips. Also, more scientific attention can be paid to the exact size and physical placement of the trap crop, and how such relates to its trapping efficiency and field-level L. pratensis pest control [18,43].

During 2016–2017 trials, L. pratensis nymphal abundance of subsequent generations was decreased on trap-cropped cotton fields and the associated leaf and boll damage rates of leaf and boll were lower than in control plots. Yet, L. pratensis abundance in trap-cropped fields still exceeded existing economic thresholds for this pest (i.e., 12, 20, 41 bugs per 100 plants at budding, blossoming and bolling stages, respectively) in local cotton fields [14]. It is not uncommon for trap cropping to be unable to fully suppress the target pest below economically-significant levels [18,44]. For instance, insecticide application was used in cotton fields with mungbean strips when A. lucorum surpassed certain population levels [31]. Hence, trap cropping for L. pratensis may need to be complemented with other control tactics, such as targeted applications of selective insecticides [1,15], pheromone-based and light-trap mass-trapping schemes (see above), augmentative biological control, or ecological engineering measures.

Our study validates the usage of sunflower as a trap crop for L. pratensis in cotton fields in southern Xinjiang, and describes the particular role of early-planted XKZ6 sunflower strips (coupled with targeted insecticide sprays) to suppress field populations of this mirid bug. Our work provides an effective L. pratensis pest management tool which can now be adapted and integrated with other tactics, in order to advance sustainable, environmentally-sound crop protection in China’s commercial cotton production.

Acknowledgments

We extend thanks to Prof. Yanhui Lu (State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, China) for his help and advice in the experimental design and also comments on an early version of this manuscript.

Data Availability

All relevant data are within the paper.

Funding Statement

This study was supported by National Key R&D Program of China (2017YFD0201900), Key R&D Program of Xinjiang Uygur Autonomous Region (2016B01001-6), the National Natural Science Foundation of Xinjiang Uygur Autonomous Region (2019D01A65), the Basic Research Operating Expenses Program of Public Welfare Research Institute from Xinjiang Uygur Autonomous Region (KY2017067).The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

References

  • 1.Jiang YY, Lu YH, Zeng J. Forecast and management of mirid bugs in multiple agroecosystem of China China Agriculture Press, Beijing: 2015. [Google Scholar]
  • 2.Liu B., Li HQ, Ali A, Li HB, Liu J, Yang YZ, et al. Effects of temperature and humidity on immature development of Lygus pratensis (L.) (Hemiptera: Miridae). Journal of Asia-Pacific Entomology. 2015; 18(2):139–143. [Google Scholar]
  • 3.Meng X., Han YF. Identification of eight common species of mirid bugs. Chinese Bulletin Entomology. 1957; 3:73–79. [Google Scholar]
  • 4.Wang JR. The first observation of three mirid bugs in cotton fields in Xinjiang. Eastern China Agriculture Science Report. 1957; 9:474–476. [Google Scholar]
  • 5.Xiao CY, Meng XL. The plant bugs collected form cotton field in China. Current Zoology.1963; 15:439–449. [Google Scholar]
  • 6.Wang JR. The control technology of Lygus pratensis. Xinjiang Agriculture Science. 1979; 3:6–8. [Google Scholar]
  • 7.Wang JR. The management of mirid bugs in early spring. Xinjiang Agriculture Science. 1966; 4:163–64. [Google Scholar]
  • 8.Wang JR, Yang HF, Meng ZJ, Ji RG. The damages of Lygus pratensis and caused cotton hollow in Xinjiang. Xinjiang Agriculture Science 1979; 3:1–6. [Google Scholar]
  • 9.Lu YH, Wu KM. Biology and Control Methods of the Mirids. Golden Shield Press, Beijing: 2008. [Google Scholar]
  • 10.Yang HF. The occurrence rule and forecast strategy of cotton mirids. Xinjiang Agriculture Science 1962; 3:111–113. [Google Scholar]
  • 11.Yang X, Jin BF, Meng JW, Zhu B. Outbreaks of Lygus pratensis in southern Xinjiang in 2003. China Cotton. 2004; 5:43. [Google Scholar]
  • 12.Li HB, Wu KM, Xu Y, Yang XR, Yao J, Wang F. Population dynamics of pest mirids in cotton filed in southern Xinjiang. Chinese Bulletin Entomology. 2007; 44(2): 219–222. [Google Scholar]
  • 13.Su LY, Yuan BZ. Occurrence and damages of Lygus pratensis and its control techniques. Shanxi Fruits. 2012; 5: 48. [Google Scholar]
  • 14.Wang W, Zhang RF, Liu HY, Zhang Y, Yao J. Control indices for Lygus pratensis (Heteroptera:Miridae) in cotton plantations in Kashgar, Xinjiang. Chinese Journel Applied Entomology. 2016; 53(5):1146–1152. [Google Scholar]
  • 15.Lu YH, Wu KM. Mirid bugs in China: pest status and management strategies. Outlooks Pest Management. 2011; 22(6):248–252. [Google Scholar]
  • 16.Cao N, Leng LY, Liu DC, Feng HZ. Study on the host plants and diet selection of Lygus pratensis. Chinese Cotton, 2017; 44(3): 27–29. [Google Scholar]
  • 17.Sun P, Yang Q, Liu DC, Gou CQ, Feng HZ. Taxis responses of Lygus pratensis to 7 different host plants. Xinjiang Agricultural Science. 2017; 54(5):925–930. [Google Scholar]
  • 18.Hokkanen HMT. Trap cropping in pest management. Annuma Review Entomology. 1991; 36(1):119–138. [Google Scholar]
  • 19.Tillman PG, Khrimian A, Cottrell TE, Lou X, Mizell RF, Johnson CJ. Trap cropping systems and a physical barrier for suppression of stink bugs (Hemiptera: Pentatomidae) in cotton. Journal of Economic Entomology. 2015; 108(5):2324–2334. 10.1093/jee/tov217 [DOI] [PubMed] [Google Scholar]
  • 20.Shelton AM, Badenes-Perez FR. Concepts and applications of trap cropping in pest management. Annual Review Entomology. 2006; 51(1):285–308. [DOI] [PubMed] [Google Scholar]
  • 21.Stern M, Mueller A, Sevacherian V, Way M. Lygus bug control in cotton through alfalfa interplanting. California Agricultural. 1969; 23:8–10. [Google Scholar]
  • 22.Stern VM, Bosch van den, Leigh TF. Strip cutting alfalfa for Lygus bug control. California Agricultural. 1964; 18, 4–6. [Google Scholar]
  • 23.Godfrey LD, Leigh TF. Alfalfa harvest strategy effect on Lygus bug (Hemiptera: Miridae) and insect predator population density: implications for use as trap crop in cotton. Environmental Entomology. 1994; 23(5):1106–1118. [Google Scholar]
  • 24.Mensah RK, Khan M. Use of Medicago sativa (L.) interplantings/trap crops in the management of the green mirid, Creontiades dilutus (Stål) in commercial cotton in Australia. Interntional Journal of Pest Management. 1997; 43(3):197–202. [Google Scholar]
  • 25.Swezey SL, Nieto DJ, Bryer JA. Control of western tarnished plant bug Lygus hesperus Knight (Hemiptera: Miridae) in California organic strawberries using alfalfa trap crops and tractor-mounted vacuums. Environmental Entomology. 2007; 36(6):1457–1465. 10.1603/0046-225x(2007)36[1457:cowtpb]2.0.co;2 [DOI] [PubMed] [Google Scholar]
  • 26.Swezey SL, Nieto DJ, Hagler J, Pickett CH, Bryer J.A, Machtley SA. Dispersion, distribution, and movement of Lygus spp. (Hemiptera: Miridae) in trap-cropped organic strawberries. Environmental Entomology. 2013; 42(4):770–778. 10.1603/EN12353 [DOI] [PubMed] [Google Scholar]
  • 27.Pansa M., Tavella L. Alfalfa management affects infestations of Lygus rugulipennis (Heteroptera: Miridae) on strawberries in northwestern Italy. Crop Protection. 2009; 28(2):190–195. [Google Scholar]
  • 28.Easterbrook MA, Tooley JA. Assessment of trap plants to regulate numbers of the European tarnished plant bug, Lygus rugulipennis, on late-season strawberries. Entomologia Experimentalis Applicata. 1999; 92(2):119–125. [Google Scholar]
  • 29.Rämert B, Hellqvist S, Ekbom B, Banks JE. Assessment of trap crops for Lygus spp. in lettuce. International Journal of Pest Management. 2001; 47(2):273–276. [Google Scholar]
  • 30.Ondiaka S, Migiro L, Rur M, Birgersson G, Porcel M, Rämert B, et al. Sunflower as a trap crop for the European tarnished plant bug (Lygus rugulipennis). Journal of Applied Entomology. 2016, 140(6):453–461. [Google Scholar]
  • 31.Lu YH, Wu KM, Wyckhuys KAG, Guo YY. Potential of mungbean, Vigna radiatus as a trap crop for managing Apolygus lucorum (Hemiptera: Miridae) on Bt cotton. Crop Protrction. 2009; 28(1):77–81. [Google Scholar]
  • 32.Chen PY, Feng HQ, Li GP, Guo XR. Analysis of trapping effect of three leguminous plants on cotton Miridae. Henan Agricultural Science. 2010; 5:66–68. [Google Scholar]
  • 33.Michaud JP, Qureshi JA, Grant AK. Sunflowers as a trap crop for reducing soybean losses to the stalk borer Dectes texanus (Coleoptera: Cerambycidae). Pest Management Science. 2007; 63(9):903–909. 10.1002/ps.1422 [DOI] [PubMed] [Google Scholar]
  • 34.Soergel DC, Ostiguy N, Fleischer SJ, Troyer RR, Rajotte EG, Krawczyk G. Sunflower as a potential trap crop of Halyomorpha halys (Hemiptera: Pentatomidae) in pepper fields. Environmental Entomology. 2015; 44(6):1581–1589. 10.1093/ee/nvv136 [DOI] [PubMed] [Google Scholar]
  • 35.Mathews CR, Blaauw B, Dively G, Kotcon J, Moore J, Ogburn E, et al. Evaluating a polyculture trap crop for organic management of Halyomorpha halys and native stink bugs in peppers. Journal of Pest Science. 2007; 90(4):1245–1255. [Google Scholar]
  • 36.Hokkanen HMT. Biological and agrotechnical control of the rape blossom beetle Meligethes aeneus (Coleoptera, Nitidulidae). Acta Entomology Fenn. 1989; 53:25–29. [Google Scholar]
  • 37.Srinivasan K, Krishna MPN. Indian mustard as a trap crop for management of major lepidopterous pests on cabbage. Tropical Pest Management. 1991; 37(1):26–32. [Google Scholar]
  • 38.Pawar DB, Lawande KE. Effects of mustard as a trap crop for diamondback moth on cabbage. Journal of Maharashtra Agricultural. University. 1995; 20:185–186. [Google Scholar]
  • 39.Pair SD. Evaluation of systemically treated squash trap plants and attracticidal baits for early-season control of striped and spotted cucumber beetles (Coleoptera: Chrysomelidae) and squash bug (Hemiptera: Coreidae) in cucurbit crops. Journal of Economic Entomology. 1997; 90(5):1307–1314. [Google Scholar]
  • 40.Khan ZR. Midega CAO, Hutter NJ, Wilkins RM, Wadhams LJ. Assessment of the potential of Napier grass (Pennisetum purpureum) varieties as trap plants for management of Chilo partellus. Entomologia Experimentalis Applicata. 2006; 119(1):15–22. [Google Scholar]
  • 41.Adler LS, Hazzard RV. Comparison of perimeter trap crop varieties: effects on herbivory, pollination, and yield in butternut squash. Environmental Entomology. 2009; 38(1):207–215. 10.1603/022.038.0126 [DOI] [PubMed] [Google Scholar]
  • 42.Goulson D. REVIEW: An overview of the environmental risks posed by neonicotinoid insecticides. Journal of Applied Ecology, 2013; 50(4):977–987. [Google Scholar]
  • 43.Fenoglio MS, Videla M, Morales JM. Evaluating trap cropping strategies for insect pest control through simulation models. Journal of Pest Science. 2017; 90(2):601–610. [Google Scholar]
  • 44.Castle SJ. Concentration and management of Bemisia tabaci in cantaloupe as a trap crop for cotton. Crop Protection. 2006; 25(6):574–584. [Google Scholar]

Decision Letter 0

Yonggen Lou

17 Jan 2020

PONE-D-19-30008

Sunflower trap cropping lowers infestation pressure and damage of Lygus pratensis in cotton fields

PLOS ONE

Dear Dr. Yao,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

I agree with the reviewer's idea. Please improve the manuscript thoroughly according to the reviewer's comments.

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Yonggen Lou

Academic Editor

PLOS ONE

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Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: No

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

**********

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PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Sunflower trap cropping lowers infestation pressure and damage of Lygus pratensis in cotton fields

The authors addressed a popular topic of agroecology. They found that sunflower strips can be a trapping plant to the mirid bug Lygus pratensis. Also, sunflower strips could significantly decrease abundance of L. pratensis in cotton field. The results are interesting and important. However, the writing is hard to be understood. I suggest the logistic and structure of the manuscript should be substantial improved. Also, I have several concerns below:

You should describe insect sampling methods very carefully. “In each plot, five points were randomly selected and 10 plants were checked per point. On each plant, the number of L. pratensis adults was visually determined and recorded”. So, 50 plants were sampled in each field, right? Maybe a sampling diagram is better to show youe method. Also, you only counted the adults, or bothadult and nymphs . There are also many nymphs in field. You did not show the nymph data in Figure 1. Why you ignore nymphs? You should add more information here.

About the field investigation, you have both sunflower and cottons. Do you investigate the abundance of Lygus pratensis in both crops? In figure 1, you showed the number of adults. Is that cotton? ZM 49 is cotton. I am confusing. I guess you investigate cotton. It makes no sense if you compare the differences between sunflowers and cotton.

You designed three treatments of planting time. In figure 3, do you combine all different time. It is inappropriate that you combine different treatment because late-planted sunflower seems more effective to control Lygus pratensis. I am also confusing that you had nymph data here. You never showed nymph data before.

The discussion is too broad.

Conclusion section. You said that early-planted XKZ6 sunflower strips (coupled with targeted insecticide sprays) to suppress field populations of bug. But I saw the abundance in cotton planted XKZ6 sunflower strips is highest based on Figure 1. Is that right?

**********

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Reviewer #1: No

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PLoS One. 2020 Aug 17;15(8):e0237318. doi: 10.1371/journal.pone.0237318.r002

Author response to Decision Letter 0

26 Mar 2020

I. Responses to the comments and suggestions of Referee

1. You should describe insect sampling methods very carefully. “In each plot, five points were randomly selected and 10 plants were checked per point. On each plant, the number of L. pratensis adults was visually determined and recorded”. So, 50 plants were sampled in each field, right? Maybe a sampling diagram is better to show your method.

Also, you only counted the adults, or both adult and nymphs. There are also many nymphs in field. You did not show the nymph data in Figure 1. Why you ignore nymphs? You should add more information here.

Reply: In term of the sampling methods, there is a writing error, we have corrected our mistake. Line108-109: changed to “In each plot, using five-point sampling method and 20 consecutive plants were checked each point”. Also, a sampling diagram (figure 1) is generated to show our method clearly.

Beginning in early June, as these first generation of Lygus pratensis nymphs become adults on spring host plants, they disperse to other host plants and then produce second generation there. In other words, before they attack the sunflower and cotton, no L. pratensis’ infestation was occurred on these two crops. Therefore, we only investigate the relative attractiveness of sunflowers and cottons to adults from entering period, ignore the nymphs here. Line110-114.

2. About the field investigation, you have both sunflower and cottons. Do you investigate the abundance of Lygus pratensis in both crops? In figure 1, you showed the number of adults. Is that cotton? ZM 49 is cotton. I am confusing. I guess you investigate cotton. It makes no sense if you compare the differences between sunflowers and cotton.

Reply: In our work, we indeed investigated the abundance of Pratensis in both sunflower and cottons. To clarify our meaning, we have now including the following in Figure 2 legends on Line 459 “Note：ZM49 is cotton, XKZ6 and SH363 are sunflower varieties.”

The aim of this research is to examine the potential of usage of sunflower as a trap crop for L. pratensis in cotton fields. Here, cotton is regarded as control group. Therefore, comparing the abundance of L. pratensis between sunflowers and cotton is requisite and meaningful. On Lines 166-169.

3. You designed three treatments of planting time. In figure 3, do you combine all different time? It is inappropriate that you combine different treatment because late-planted sunflower seems more effective to control Lygus pratensis. I am also confusing that you had nymph data here. You never showed nymph data before.

Reply: In figure 4, we only used the early-planted XKZ6 rather than combing all different time. The aim of the initial field-plot trials is to determine the suitable inter-planted sunflower strips, and the results have indicated the early-planted XKZ6 more effective to attract Lygus pratensis adults, in this context, this treatment was undoubtedly used for subsequent analysis.

The emphases of these two treatments are different, in figure 2, first generation of L. pratensis as reproductive adults dispersed to other plants, and then produced second generation there. Therefore, we ignore nymphs here. In figure 4, to assess the role of sunflower strips on population dynamics of L. pratensis in cotton fields, the abundance of L. pratensis including adults and nymphs were investigated.

4. The discussion is too broad. Conclusion section. You said that early-planted XKZ6 sunflower strips (coupled with targeted insecticide sprays) to suppress field populations of bug. But I saw the abundance in cotton planted XKZ6 sunflower strips is highest based on Figure 1. Is that right?

Reply: The objective of our work is to assess the relative attractiveness of sunflower (Helianthus annuus) to Lygus pratensis adults in local cotton plots. As shown in Figure 1, the abundance in cotton early-planted XKZ6 sunflower plots is highest, thus we concluded that establishment of sunflower strips could contribute to suppress field populations of bug in cotton crops. Our conclusion is coincident with figure 2.

The conclusion section was outlined in Discussion (L203-L209): “Our study validates the usage of sunflower as a trap crop for L. pratensis in cotton fields in southern Xinjiang, and describes the particular role of early-planted XKZ6 sunflower strips (coupled with targeted insecticide sprays) to suppress field populations of this mirid bug.”

Attachment

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Decision Letter 1

Yonggen Lou

23 Apr 2020

PONE-D-19-30008R1

Sunflower trap cropping lowers infestation pressure and damage of Lygus pratensis in cotton fields

PLOS ONE

Dear Yao,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

==============================

Please improve the manuscript according to the two reviewers' comments.

==============================

We would appreciate receiving your revised manuscript by Jun 07 2020 11:59PM. When you are ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter.

To enhance the reproducibility of your results, we recommend that if applicable you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

Please include the following items when submitting your revised manuscript:

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). This letter should be uploaded as separate file and labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. This file should be uploaded as separate file and labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. This file should be uploaded as separate file and labeled 'Manuscript'.

Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.

We look forward to receiving your revised manuscript.

Kind regards,

Yonggen Lou

Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

Reviewer #3: (No Response)

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Partly

Reviewer #3: Partly

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: I Don't Know

Reviewer #3: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: Yes

Reviewer #3: No

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: Yes

Reviewer #3: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: 1. The title is not good enough. The following two titles are suggested: Field evaluation of sunflower as a potential trap crop of Lygus pratensis in cotton fields or Intercropping sunflower reduces the infestation and damage of Lygus pratensis in cotton fields

2. The introduction is not strong enough in the present version, and more latest literatures (published in the international journals) of intercropping effect on herbivorous pests and the underline mechanisms should be introduced.

3. The diagram in the current version is not the really diagram, and I made no sense from it. Please referred to other published papers.

4. LSD was abandoned in the present. Turkey’s test is suggested to analyze your data.

5. The language of the paper should be polished.

Reviewer #3: In this paper, the occurrences of Lygus pratensis were analyzed between different sunflower and cotton crops in field. Next another test were designed to estimate the influence of L. pratensis population on cotton crops with or without sunflower border strips. It reported that adult abundance of L. pratensis was highest on early-planted sunflower in field, and sunflower could reduce the damage of cotton by L. pratensis. The results is very interesting and important for IPM on cotton cultivation, but the writing and some experiments of this paper need to be further improved. Some comments as below,

1. Why did you use five-point sampling method? As Yao et al (2016) reported that the spatial distribution pattern L. pratensis were aggregated distribution.

2. Please give location of the sample site when using five-point sampling？Especially when collecting data from trap-cropping field with two 1-m wide strips of sunflower on the opposite borders of the field, parallel to the cotton rows.

3. As results of figure 2, the size of plant is important factor for L. pratensis to select plants. It is not very available to say the sunflower more attractive to cotton. Could you please show some other data such as comparing the attractive ability between same size cotton or sunflower.

4. Please check the data of Table 1 that in 2016, the p value of the adults, Nymphs were 0.0622 and 0.0430 respectively, but the p value of the total the adult and nymphs was 0.0167 not in range 0.0430~0.0622, is right?

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #2: No

Reviewer #3: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at figures@plos.org. Please note that Supporting Information files do not need this step.

PLoS One. 2020 Aug 17;15(8):e0237318. doi: 10.1371/journal.pone.0237318.r004

Author response to Decision Letter 1

3 Jun 2020

Dear editors,

Thank you very much for your attention and careful consideration to our manuscript. We appreciate reviewers very much for their constructive comments and suggestions on our manuscript.

We have carefully considered your and referee’s suggestion and comments and revised our manuscript according to these precious comments. Those comments are invaluable for improving our paper. We have accordingly revised the manuscript carefully and hope that this new version could be accepted for publication in PLOS ONE The main corrections and the responds to the comments point to point are given below:

I. Responses to the comments and suggestions of Referee

1. The title is not good enough. The following two titles are suggested: Field evaluation of sunflower as a potential trap crop of Lygus pratensis in cotton fields or Intercropping sunflower reduces the infestation and damage of Lygus pratensis in cotton fields.

Reply: Thanks for the reviewer's suggestion, and the title has been changed to "Field evaluation of sunflower as a potential trap crop of Lygus pratensis in cotton fields"(Line 5-6)

2. The introduction is not strong enough in the present version, and more latest literatures (published in the international journals) of intercropping effect on herbivorous pests and the underline mechanisms should be introduced.

Reply: Thanks for the suggestion, and it has been supplemented in the revised manuscript.

3. The diagram in the current version is not the really diagram, and I made no sense from it. Please referred to other published papers.

Reply: Thanks for the suggestion, and referred to the other published papers, we have been re-made the diagram in the revised manuscript.

4. LSD was abandoned in the present. Turkey’stest is suggested to analyze your data.

Reply: Thanks for the suggestion. Because the population dynamics of Lygus pratensis on cotton and sunflower are all showed seasonal changes, so the data analysis are as follows: Differences in the abundance of L. pratensis (including adults, nymphs, and total population, as three counts) in cotton and sunflower plots (2015-2016) or in cotton fields with/without sunflower strips (2016-2017) were analyzed by a repeated-measures analysis of variance (ANOVA) using SAS PROC MIXED, and the means were compared by the least significant difference test (LSD). The data were log10(n+1)-transformed before analysis. The mean abundances of L. pratensis adults in plots of cotton and sunflower during 2015-2016 were compared using one-way ANOVA followed by Tukey’s HSD for multiple comparisons. Mean abundances of L. pratensis population, the damage rate of leaves and bolls (arcsin-transformed), and the number of mature bolls in cotton fields with/without sunflower strips during 2016-2017 were compared through non-paired t-tests.

5. The language of the paper should be polished.

Reply: Thanks for the reviewer's suggestion, the language has been improved and polished in the revised manuscript.

II. Responses to the comments and suggestions of Referee 2

1. Why did you use five-point sampling method? As Yao et al (2016) reported that the spatial distribution pattern L. pratensis were aggregated distribution.

Reply: As Jiao et al (2012) reported that the spatial distribution pattern of Apolygus lucorum (Hemiptera: Miridae) is aggregated distribution. five-point sampling method is usually used for the investigation and sampling of Apolygus lucorum in fields (Wu et al, 2002; Lu et al, 2008; Lu et al, 2009), so we borrowed their method, using five-point sampling method in this paper.

2. Please give location of the sample site when using five-point sampling？Especially when collecting data from trap-cropping field with two 1-m wide strips of sunflower on the opposite borders of the field, parallel to the cotton rows.

Reply: In order to show our sampling method more intuitively, we made a sampling diagram (Figure 1b)

3. As results of figure 2, the size of plant is important factor for L. pratensis to select plants. It is not very available to say the sunflower more attractive to cotton. Could you please show some other data such as comparing the attractive ability between same size cotton or sunflower.

Reply: As you said, the size of plant is important factor for L. pratensis to select plants. In this paper, the two most common sunflower varieties (XKZ6 and SH363) were selected to investigated the abundance of Lygus pratensis with different varieties and planting dates, and cotton was investigated at the same time. According to previous habit, sunflower and cotton were all investigated 100 plants each time. But ignore the impact of plant size, this is indeed the negligence of our work.

And on the basis, we investigated the population of Lygus pratensis on sunflower(XKZ6) and cotton with the same size in 2017. The result showed that, compared to cotton, sunflowers have more attractive ability to Lygus pratensis. But this data has already appeared in another submitted paper.

4. Please check the data of Table 1 that in 2016, the p value of the adults, Nymphs were 0.0622 and 0.0430 respectively, but the p value of the total the adult and nymphs was 0.0167 not in range 0.0430~0.0622, is right?

Reply: In response to your questions, we checked and analyzed the data again.

Compared with control treatments, population levels of L. pratensis adults and nymphs were markedly lower in cotton fields with sunflower borders. So the population levels of L. pratensis all individuals (nymphs and adults) were lower even more in cotton fields with sunflower borders, compared with control treatment. Therefore, the p value of the total adults and nymphs was 0.0167 not in range 0.0430~0.0622.

We hope that the revised manuscript will meet with formal acceptance.

Again, we thank you and the reviewers for your time and effort in reviewing this manuscript.

Kindest regards.

Yours,

Renfu Zhang

Institute of Plant Protection

Xinjiang Academy of Agricultural Sciences

No.403, Nanchang Road

Urumqi, Xinjiang 830091, China

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Decision Letter 2

Yonggen Lou

22 Jun 2020

PONE-D-19-30008R2

Field evaluation of sunflower as a potential trap crop of Lygus pratensis in cotton fields

PLOS ONE

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Reviewers' comments:

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Reviewer #3: (No Response)

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Reviewer #2: All questions has been answered and all responses meet formatting specifications. Thank you for your revison.

Reviewer #3: It is interesting results of this text that sunflower can be an effective trap crop for L. pratensis in field. The writing of the paper should to be polished and concise before be published, and other some suggest or question:

1.Line 35, integrated pest management (IPM), please capitalize the first letter of the first word.

2. in text, there are some presentation like "F=70.88，df=6,14， P<0.0001" ,you can try like"F(6,14)=70.88, P=... "

3.Line 160, "F=70.88，df=6,14， P<0.0001", the sampling times is 16 in range 6/3 to 8/17 in Figure 2, please check "df=14" is right?

4. Also please check Ndf number of sampling period=8, you need to explain how to select data for analysis. please see times of sampling is 11 as showed in figure 4.

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PLoS One. 2020 Aug 17;15(8):e0237318. doi: 10.1371/journal.pone.0237318.r006

Author response to Decision Letter 2

23 Jul 2020

1. Line 35, integrated pest management (IPM), please capitalize the first letter of the first word.

Reply: Thanks for the referee's suggestion. We have capitalized the first letter of the first word of integrated pest management (IPM) (Line 35).

2. in text, there are some presentation like "F=70.88, df=6,14, P<0.0001", you can try like" F (6,14) =70.88, P=... "

Reply: Thanks for the referee's suggestion. We have modified the format like your suggestion (Line 156-160 and 175-182).

3.Line 160, "F=70.88，df=6,14, P<0.0001", the sampling times is 16 in range 6/3 to 8/17 in Figure 2, please check "df=14" is right?

Reply: Thanks for the referee's suggestion. Population levels of L. pratensis adults among all seven treatments were analyzed using repeated measures ANOVA in 2015 and 2016, each of the above treatments was established in 3 field plots (i.e., replicates). it means that, 7 treatments, each treatment replicates 3 times, total of 21 plots in this test. Therefore, the correct is df=6,12. Through analysis again, found that this indeed a mistake. Thank you very much for your attention and careful review(Line 175-182).

4. Also please check Ndf number of sampling period=8, you need to explain how to select data for analysis. please see times of sampling is 11 as showed in figure4.

Reply: Thanks for the referee's suggestion. Difference in the abundance of L. pratensis (including adults, nymphs, and total population, as three counts) in cotton fields with/without sunflower strips (2016-2017) were analyzed by a repeated-measures analysis of variance (ANOVA) using SAS PROC MIXED, and the means were compared by the least significant difference test (LSD). In 2016 and 2017, L. pratensis abundances in both cotton fields were below the existing economic thresholds for this pest (i.e., 20 bugs per 100 cotton plants at blossoming stage; Wang et al., 2016) after middle July. Hence, only population abundance records from early June to mid-July were included in the repeated-measures ANOVA and non-paired t-tests, select sampling time 8 times for statistical analysis. Detailed explanation showed in the statistical analysis (line 134-147).

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Decision Letter 3

Yonggen Lou

27 Jul 2020

Field evaluation of sunflower as a potential trap crop of Lygus pratensis in cotton fields

PONE-D-19-30008R3

Dear Dr. Yao,

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Yonggen Lou

Academic Editor

PLOS ONE

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Reviewers' comments:

Acceptance letter

Yonggen Lou

5 Aug 2020

PONE-D-19-30008R3

Field evaluation of sunflower as a potential trap crop of Lygus pratensis in cotton fields

Dear Dr. Yao:

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on behalf of

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Academic Editor

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