Laboratory and Field Evaluation of Insecticide Des against Ascotis Selenaria Reciprocaria Walk. (Geometridae) On Coffee in Kenya

Thumbnail Image
Evans, D.E.
Journal Title
Journal ISSN
Volume Title
Thirty-six insecticides were tested in the laboratory only and six in both laboratory and field for the control of Ascotis selenaria reciprocaria Walk. (Geometridae) a defoliator of Coffee arabica in parts of Kenya and Tanzania, and of citrus in South Africa. The laboratory trials assessed the contact activity, stomach poison activity and persistence (of two only) of the insecticides. Only two compounds, Lannate, (S.methyl N ((methylcarbamoyl) oxy) thioacetimidate) and Sandoz 6538 (an organophosphoric acid ester), were found to have both good contact and stomach poison activity. Lannate was found to be more persistent than Sandoz 6538. The field trials showed that naled (2.0 lb.),mevinphos (0.6 lb.) and methidathion (0.9 lb. active ingredient per acre) were less effective than the standard treatment of a "knockdown" pyrethrins spray combined with DDT stem dusting. Endosulfan, at 1.1 lb. per acre, was as effective as the standard. Lannate, at 0.5 and 0.33 lb., and Sandoz 6538, at 0.75 and 0.5 lb. active ingredient per acre, were more effective than the standard and of these four treatments Lannate, at 0.5 lb., was the most active. The superiority of Lannate appeared to be related to its persistence. Biossays with Aphelinid and Encyrtid parasites of Coccus alpinus De L. showed that Lannate was absorbed into the leaf tissue quite rapidly and would not, normally, be too hazardous to beneficial insects. Liquoring tests showed that Lannate and Sandoz 6538 caused no off-flavours. Residue data were obtained from Lannate only, which was found to be suitable for use on coffee.
East African Agricultural and Forestry Journal, XXXV (3), pp. 311-321