Changes in the density of haemocytes/mm³ of haemolymph in the nymphs and adults of red cotton bug, Dysdercus cingulatus Fabr. (Hemiptera: Pyrrhocoridae) treated with insecticides of diverse groups

Effect of three chemically different insecticides was assessed on the changes in Total Haemocyte Counts, - (THC) in the red cotton bug, Dysdercus cingulatus (Hemiptera: Pyrrhocoridae). One μl doses of four concentrations ranging from Lc₃₀ – Lc₉₀ of an organophosphate, a carbamate and a synthetic pyrethroid were individually applied topically on 5th instar nymphs. The changes in THCs were followed daily within the 5^th instar stage and then after moulting to adults. The lower concentrations generally had a positive effect on THC whereas the higher concentrations induced significant reduction. The trend in the change in population of haemocytes was apparently same in all the affected nymphs and adults irrespective of the type of insecticide applied.