TABLE 4.

Effects of carbofuran and P. fluorescens strains on gall formation caused by M. incognita and on soil and root populations in tomato and soybean grown under glasshouse conditions^a

Strain or statistic	Galls/g rootb		M. incognita organisms/g rootc		M. incognita organisms/ 100 cm3 soil
	Tomato	Soybean	Tomato	Soybean	Tomato	Soybean
Control	101a	81a	136a	121a	1,524a	1,330a
Carbofuran	34c	29c	62c	52c	625c	380c
CHA0	62b	46bc	82bc	80b	1,238b	1,070b
CHA89	86ab	69ab	116a	107a	1,461a	1,196ab
CHA805	76ab	55b	107ab	97ab	1,456a	1,218ab
LSDd	26	23	30	25	164	153

^aSandy loam soil (sand:silt:clay, 70:19:11; pH 8.1; moisture holding capacity, 39%) from Karachi was placed in plastic pots (8-cm diameter). After removing the upper 2-cm layer of soil, 2.2 × 10⁸ to 3.1 × 10⁸ CFU ml⁻¹ of bacteria suspended in 25 ml sterile 100 mM MgSO₄ or 120 mg kg⁻¹ carbofuran (a granular nematocide purchased from Pak Agrochemicals, Karachi, Pakistan) was drenched. Soil drenched with 25 ml of sterile 100 mM MgSO₄ was used as a control. After treatment, three tomato seedlings (cv. SUN 6002 PVP) were planted in each pot. After 1 week, 2 × 10³ M. incognita juveniles were added to each pot. The suspension was adjusted to 500 juveniles ml⁻¹ by adding tap water, and a total of 4 ml was pipetted into four holes made around the seedlings in the soil. In another series of pots, after bacterial and chemical treatments, eight soybean (Glycine max L. cv. NARC I) seeds were sown in each pot, and after germination four seedlings per pot were retained. One week after emergence, the seedlings were infested with M. incognita juveniles as described above.

^bGall formation is expressed as the number of galls per gram of root after 45 days.

^cM. incognita populations are expressed as the number of individuals per gram of root or per 100 cm³ of soil (16, 22) after 45 days. Data for each strain and plant system were obtained from four different experiments with four repetitions. Means of the experiments in each column followed by different letters are significantly different (P ≤ 0.05) according to Fisher's test.

^dLSD, least significant difference.