Citricola Scale Insecticide Efficacy Trials, 1994,1995

Insecticides were evaluated for efficacy against various stages of citricola scale on citrus compared with a water application, a standard organophosphate insecticide treatment, and a 0.33% narrow range Uni-Par spray oil treatment. Insecticides were applied to individual 20 year old ‘Washington navel’ orange trees at the Lindcove Research and Extension Center, Exeter, CA. Late summer applications (31 Aug 1994) targeted 1st instar nymphs on the leaves. Late spring applications (2 Jun 1995) targeted mature females and newly deposited eggs on twigs. Six replications of single tree treatments were applied at 300 gpa (3-4 gal/tree), 300 psi using a Bean hand-sprayer. During the spring (May-Jun) live female citricola scale on 10 twigs (approximately 30 cm in length) per tree were counted. During summer and fall (Jul-Oct) live 1st instar nymphs on 10 or 20 leaves collected from the northeast quadrant of each tree were counted.