Management of root-knot disease in eggplant through the application of biocontrol fungi and dry neem leaves

摘要

The incorporation of dry neem leaves into the soil significantly enhanced the yield of uninoculated eggplant, but aldicarb treatments at 4 kg a.i./ha proved to be phytotoxic. Inoculation with root-knot nematode Meloidogyne incognita (1500 J _2/plant) caused a significant decrease in both the plant growth (12.5%) and the yield (11.9%) of eggplant cv. Pusa Purple Round. Treatments involving neem leaves, Pochonia chlamydosporia, Paecilomyces lilacinus, Trichoderma harzianum, or aldicarb reduced the suppressive effect of the nematode, leading to a significant increase in the dry matter production and yield of inoculated plants compared to the inoculated control. Neem leaves induced a 19% increase in the weight of fruits/plant of inoculated plants; similar results were obtained using P. chlamydosporia, P. lilacinus, T. harzianum, and aldicarb treatments, with increases over the inoculated control of 11%, 14%, 6%, and 8%, respectively. Declines in galling, egg mass production, and fecundity were found to be greater with aldicarb and lower with the neem leaf treatment. The incorporation of neem leaves into biocontrol treatments increased the efficiency of the treatment and resulted in a 17%, 21%, and 14% increase in the yield with P. chlamydosporia, P. lilacinus, and T. harzianum treatments, respectively. Decreases in galling and egg mass production were also greater in the presence of neem leaves than in methods using the biocontrol agents alone. The percentages of infection in adult nematode females and egg masses with P. chlamydosporia, P. lilacinus, and T. harzianum applied to plants were considerably greater in the presence of neem leaves (77%-92% and 43%-57%) than in their absence (69%-87% and 33%-47%).