INSECTICIDAL CONTROL OF PEPPER WEEVIL AND INCIDENCE OF GREEN PEACH APHID ON JALAPEÑO PEPPER, 2003

Pepper weevil is the major pest of all pepper varieties in the southern parts of the US, due in part to the impossibility of controlling the cryptic immature stages. In this study, we looked at new products, application timing, and rotational protocols to increase options and improve efficiency of older products for controlling this pest. Greenhouse-raised pepper plants were transplanted on 26 Feb at 10-inch spacing in single rows on two sets of three beds 240 ft in length and covered with polyethylene film mulch. Water and fertilizer were provided through Netafim drip tape with 12-inch emitter spacing. The center bed in each set of three was left untreated to serve as a source of weevils. Each treated bed was divided into plots 33 ft long to which treatments were assigned in an RCB design with four replications. Peppers infested with weevil larvae were placed under the plants in the inoculum row on 25 Mar to introduce the pest into the trial area. A survey on 14 Apr showed that 6 out of 50 peppers collected from the inoculum rows contained larvae. No adults were found and no infested peppers were found in the treated rows. Prokil Cryolite 96 was tested as a deterrent prior to the detection of weevils with 6 weekly applications at 4 lb per acre beginning on 12 Mar or four weekly applications at 6 lb per acre were beginning on 19 Mar (Table 1). A high clearance sprayer was used operating at 200 psi with the spray delivered through two vertical booms, each fitted with two ceramic yellow Albuz hollow cone nozzles for a total of 44 gpa. The regimen was changed 22 Mar to an Actara/Vydate rotation on detection of weevils, at which time the remaining four weekly treatments were also initiated (Table 1). Pepper weevil damage was monitored by collecting fallen fruit from both sides of 21 centrally located plants per plot on 21 and 28 Apr and 5, 12, and 19 May. An infestation of green peach aphid, Myzus persicae, first observed on 21 Apr, was rated on 20 leaves per plot on 5, 12 and 19 May using the following system: 1 = no aphids, 2= 1-2 aphids per leaf, no significant plant damage and 3 = 10+ aphids per leaf causing significant plant stress. Mature peppers were harvested from 21 plants per plot on 21 Apr and the percentage of infested fruit was estimated by dissecting 50 peppers per plot for weevils or damage. On 20 May, all fruit 2.5 inches or more in length was harvested and weighed from the same 21 plants per plot harvested earlier. Weight of marketable fruit was estimated by dissecting a random sample of up to 50 harvested fruit per plot to obtain a percentage infested with weevils and adjusting the total weight accordingly. Data were subjected to ANOVA and means were separated using LSD (P = 0.05).