Tolerance of Aphytis melinus DeBach (Hymenoptera: Aphelinidae) to 20 orchard chemical treatments in relation to integrated control of red scale, Aonidiella aurantii (Maskell) (Homoptera: Diaspididae)

Abstract

The toxicity of 20 orchard chemicals at field rates was determined for all stages of Aphytis melinus in the laboratory. The insecticides Bacillus thuringiensis + surfactant, endosulfan, pirimicarb: the miticide cyclosulfyne : the herbicides and plant growth regulators dimazide, diuron, gibberellic acid: the fungicide copper oxychloride: the nutrient mixture zinc oxide, manganese sulphate and urea : and the surfactant nonyl phenol ethoxylate (9 Eto) appear safe for use in citrus groves containing A. melinus. The herbicide dalapon + surfactant and the fungicide Bordeaux mixture were moderately toxic to immatures, and the herbicide bromacil was moderately toxic to adults. However, it is considered that careful application of these treatments is safe. The organophosphorus insecticides azinphos-methyl, maldison and parathion; the insect growth regulator hydroprene; and the miticide cyhexatin were highly toxic to either juvenile or adult stages. White oil, recommended for integration with A. melinus, was highly toxic to immature stages. This anomalous result is discussed in terms of spray distribution and integrated control of red scale on citrus