Field evaluation of indigenous biopesticides and resident bioagents for pest management in sorghum-cowpea intercrop.

摘要

The efficacy of the following treatments against pests and pathogens of a cowpea (cv. UPC 5286)-sorghum (cv. MP Chari) intercropping system was evaluated in Jhansi, Uttar Pradesh, India, during 2004-06: (T1) seed treatment (ST) with Trichoderma viride at 5 g/kg; (T2) ST with Paecilomyces lilacinus at 5 g/kg; (T3) ST with neem seed powder at 50 g/kg; (T4) spraying of cow dung + urine extract at 30 and 45 days after sowing (DAS); (T5) spraying of 3% neem seed extract at 30 and 45 DAS; (T6) T1 + T4; (T7) T2 + T4; (T8) T3 + T4; (T9) T1 + T5; (T10) T2 + T5; (T11) T3 + T5; and (T12) untreated control. The major insect pests were leafhoppers (Empoasca fabae) and defoliators (Plusia nigrisigna and Pagria signata [Colposcelis signata]) on cowpea, and shoot fly (Atherigona soccata) on sorghum. All the treatments significantly reduced the pest incidence. T5 resulted in the lowest level of damage in both crops (4.13-5.50%). The dominant plant parasitic nematodes were root-knot nematodes (Meloidogyne incognita and M. javanica), followed by Rotylenchulus reniformis, Tylenchorhynchus vulgaris, Helicotylenchus dihystera and Pratylenchus zeae. ST with Paecilomyces lilacinus singly or in combination with sprayed treatments was the most effective in the reduction of the total nematode population (73%), especially the populations of root knot nematodes in cowpea. The lowest incidence of leaf spot (caused by Gloeocercospora sorghi) was obtained with T1, T3, T6, T8 and T11 (50.00, 33.30, 33.30, 50.00 and 33.30%, respectively). The highest mean total green fodder yield was recorded for T6 (232.13 quintal/ha). [1.0 quintal=100.0 kg].