Table 3. Seasonal mean population density of cotton aphids, predators (coccinellids, chrysopids, anthocorids, spiders) and aphid parasitoids during 2011, 2012 and 2013 at Langfang experimental station (Yellow River Region of China).
| Seasonal mean population density (SEM) | |||
|---|---|---|---|
| Insects guild | 2011 | 2012 | 2013 |
| Cotton aphids | 1399.0 ± 76.3c | 26345.6 ± 15948.1a | 3430.8 ± 112.3b |
| Coccinellids | 289.0 ± 15.5a | 235.7 ± 12.4a | 223.7 ± 100.6b |
| Chrysopids | 88.3 ± 9.9c | 63.3 ± 5.5a | 25.7 ± 3.0c |
| Anthocorids | 138.0 ± 10.8b | 213.3 ± 12.7a | 132.7 ± 13.1b |
| Spiders | 140.7 ± 9.3b | 279.3 ± 17.1a | 295.3 ± 12.0a |
| Aphid parasitoids | 192.0 ± 41.5b | 340.0 ± 48.0a | 181.3 ± 18.5b |
Means with the same letter across sampling years are not significantly different (Student-Neuman-Keuls means separation test, α = 0.05).