Secondary effects of 40 pesticides on Leptomastidea abnormis - Grlt. - (Hym. Encyrtidae) and Scymnus includens Kirsch (Col. Coccinellidae), important natural enemies of Planococcus citri (Risso).
With a view to the selection of insecticides for the integrated control of Planococcus citri (Risso) on Citrus in Italy, 40 commercial products were tested in the laboratory for their comparative toxicity to two natural enemies of this mealybug, the parasite Leptomastidea abnormis (Gir.) and the predator Scymnus includens (Kirsch) [cf. two preceding abstracts]. The Encyrtid was exposed to branches of oranges that had been sprayed with the materials at normal rates (although they were not infested by P. citri), and the Coccinellid to sprayed potatoes infested with the mealybug. The level of toxicity and lethal persistence were determined for each product, and details of the results are given in tables. Those least harmful to L. abnormis and S. includens were lead arsenate, a preparation of Bacillus thuringiensis, binapacryl, a mixed spray of chlorfensulphide (CPAS) and chlorfenethol (DMC), demeton, dicofol, dimethoate, endosulfan, tetrachlorvinphos (Gardona), gamma BHC (lindane), MNFA (N-methyl-N-(1-naphthyl)fluoroacetamide), nicotine, light mineral oil, pyrethrum, pirimicarb, tricyclohexyltin hydroxide (Plictran), barium polysulphide, a mixture of prothoate and tetradifon, Thiofanate (1,2-bis(3-ethoxycarbonyl-2-thioureido)benzene), zineb and a mixture of zineb and copper oxychloride.<new para>ADDITIONAL ABSTRACT:<new para>In order to select pesticides for use in integrated control programmes some 40 commercial products were tested in the laboratory against L. abnormis and S. includens, parasite and predator, respectively, of P. citri. The results are tabulated. Some 21 products which had the least harmful effects are suggested for integrated control programmes.