Insecticidal Control of Citrus Leafminer, 2017

A field trial to determine the efficacy of insecticides to protect citrus foliage against citrus leafminer was conducted on 1-yr-old and 2-yr-old ‘Tango’ mandarins at the Lindcove Research and Extension Center, Exeter, California. Insecticides were applied to six trees per treatment in a CRD using a hand wand with a D6 nozzle on a 100-gal high pressure D30 diaphragm pump sprayer with mechanical agitation applied at 200 psi. Treatments were applied in 100 gal of water per acre on 3 Oct. All treatments were applied with 0.5 or 1.0% IAP Summer 415 oil. Four to 15 young flush leaves that could be utilized by citrus leafminer larvae were collected from four branches per tree and examined under a dissection microscope at weekly intervals during Oct and early Nov. The mean numbers of live larvae per suitable leaf were compared between treatments using ANOVA and the means were separated according to Fisher’s LSD (P = 0.05) after log₁₀ (x+1) transformation.

Minecto Pro applied as 10 or 12 fl oz significantly reduced the mean number of larvae per suitable leaf for 6 or 7 sample dates after treatment (Table 1). The Actara, Movento, and Minecto Pro 8 fl oz treatments reduced the mean number of larvae/leaf for 3–4 wk. By week 8, the mean numbers of larvae/leaf for all treatments were not significantly different from the untreated control.

This research was supported by the Citrus Research Board and industry gifts of pesticide and research funding.