Author : Suyadi

Summary : Field and pot experiments were simultaneously conducted to compare the effectiveness of bioact (seed treatment and drenching with 50 ml of 100 g bioact/20 liter water suspension), carbofuran (2.0 kg a.i./ha), and chicken dung (5 t/ha) in controlling reniform nematode (Rotylenchulus reniformis) and increasing yield of field and potted tomato (Lycopersicon esculentum Mill). Untreated check and check with organic fertilizer application (87.5 kg N, 61 kg Pp5, and 92 kg Kp/ha) were used as a bases for comparison. Chicken dung, bioact, and carbofuran treatments reduced the population of the reniform nematode below the initial population at midcropping. Only chicken dung and carbofuran reduced the nematode population at last harvest while inorganic fertilizer increased the nematode population. Owing to low nitrogen availability in the experimental area, application of inorganic fertilizer and chicken dung increased tomato yield. Carbofuran also increased the yield by 27 percent, while bioact did not significantly influence the yield.

Economic analyses of tomato production per hectare showed that chicken dung, inorganic fertilizer, and carbofuran treatments gave net added returns of P29,840.00, P26,094.00, and P14,597.00, respectively. Based on regression analyses, about 10 percent of potted tomato yield was lost because of reniform nematode at Pi 102/50-cc soil on treated check. Increasing soil fertility by applying inorganic fertilizer or chicken dung, without nematode infestation (Pi=O), increased yield by 35 percent and 27 percent, respectively. The effectiveness of inorganic fertilizer, carbofuran, chicken dung, and bioact to increase the yield decreased by 7.2 percent, 5.2 percent, 3.2 percent, and 1.4 percent, respectively per unit (20.4/50-cc soil) of increase in Pi. The growth factor of reniform nematode was population dependent.

The effect on field tomato yield of chicken dung due to nematode control was 15 percent, while the effect due to increased soil fertility was 34 percent.