Survey of Rice Pests in Azad Jammu & Kashmir and Potential of Dragonflies as Bio-Control Agents

Abstract

A survey was undertaken to collect the insect pests of rice and dragonflies visiting rice fields from various localities of Azad Jammu & Kashmir. The number of insect pests and dragon fly species recorded were 28 and 14 respectively. The feeding capacity of 11 dragonfly species on some insect pests of rice in a day (10 hours) was determined by forced feeding. The adults of Orthetrum sabina consumed, on an average, 9.05, 8.50, 7.1·5, 7.35, 71.20, 12.40, 113.15, 4.25, 6.90 and 4.75 while those of 0. pruinosum neglectum 3.95, 4.50, 8.00, 9.00, 64.60, 3.65, 32.20, 3.80, 4.85 and 7.00, 0. glaucum 3.20, 3.75, 5.50, 4.50, 59.95, 2.80, 30.05, 3.30, 3.50 and 5.60, 0. triangulare triangulare 3.00, 3.70, 5.60, 4.05, 61.50, 3.00, 29.80, 7.00, 3.95 and 4.50, Crocothemis servilia 4.00, 4.55, 7.50, 8.10, 43'.30, 2.80, 21.00, 2.40, 3.50 and 2.90, C. erythraea 3.45, 3.35, 6.00, 5.60, 23.85, 2.95, 16.25, 2.25, 2.50 and 4.60, Pantala flavescens 2.40, 2.70, 2.20, 7.60, 16.25, 2.20, 9.55, 2.05, 3.00 and 6.65, Sympetrum commixtum 2.35, 2.25, 8.80, 4.70, 9.35, 2.75, 6.70, 3.65, 7.40 and 3.40, Palpopleura sexmaculata sexmaculata 2.65, 2.00, 8.35, 3.80, 8.65, 1.80, 6.10, 3.10, 1.30 and 3.10, Acisoma panorpoides panorpoides 2.10, 1.75, 3.40, 5.55, 7.95, 1.65, 5.90, 3.05, 3.70 and 1.65 and Trithemisfestiva 1.45, 1.35, 2.25, 3.30, 7.00, 1.25, 4.40, 3.10 and 2.60 yellow stem borers, white stem borers, hairy caterpillars, rice skippers, whitebacked planthoppers, white leafhoppers, green leafhoppers, rice bugs, cicadellid leafhoppers and grasshoppers (Oxya spp.) respectively in 10 hours. The females of all the species proved to be the most voracious feeders as compared with their males. Orthetrum sabina was found to be the most voracious feeder followed by 0. pruinosum neglectum, 0. triangulare triangulare, 0. glaucum, Crocothemis servilia, 0. erythraea, Pantala flavescens, Palpopleura sexmaculata sexmaculata, Sympetrum commixtum, Acisoma panorpoides panorpoides and Trithemis festiva. The population density of dragonflies was maximum from middle of August to the end of September. However, it was at peak from last week of August to 3rd week of September. The population then declined as the crop matured and the pest population become low. The studies on the seasonal abundance of insect pests of rice, namely, rice skipper, grasshoppers, green leafhopper, white leafhopper, hairy caterpillar, rice bug, rice stem borers and Poophilus species were conducted at four localities i.e., Hajeera, Mandhole, Harighale and Banipasari during the crop season 1996-97. The population ofrice skipper and grasshoppers was somewhat higher than other insect pests. However, the population of different insect pests was higher from the 2nd week of August to the 4th week of September. The population then decreased afterwards as the crop matured.The efforts were made to evaluate the feeding potential of dragonflies in the field cages. They did not show any activity and interest in their prey due to their captivity. In view of this dragonfly attitude, the relationship between the population of dragonflies and insect pests of rice was observed by the multiple linear regression equation. The statistical analysis revealed that the dragonflies had negative regression coefficient with the population density of all the insect pests. It indicated that the pest population was decreased with the corresponding increase in dragonflies population. However, their feeding behaviour was not similar at all the localities but differed from locality to locality