A study was conducted to determine the effects of repeated insecticide applications on leaf niner and parasitoid populations on spring melons. After four applications, none of the insecticides induced large build-ups of leafminer larvae. A new material, AC 303630, was very effective in maintaining low numbers of pupae. However, the results of this preliminary test indicate that all insecticides tested had a negative impact on the parasitoid population. In general, in the absence of insectcides, parasitoids were capable of maintaining L. sativae populations at low levels in the experimental plots.

Foliar insecticides for whiteflies (Bemisia sp., WF) were applied as a supplementary control measure at 6 weeks after treatment with imidacloprid (Admire®) at planting time of melons. Beauveria bassiana fungus spores (Mycotrol®), pyriproxyfen (S-71639, Valent), and azadirachtin (Align®) are non-conventional insecticides that could be safer on beneficial parasites and predators. The number of eggs and nymphs counted at all rating dates for all treatments were not significantly different from the foliarly untreated check. Mycotrol treated melons showed higher number of nymphs following the second application. The Align treatment tended to exhibit higher number of nymphs after two applications. The addition of an adjuvant did not appear to enhance pyriproxyfen efficacy.

Beauveria bassiana is a naturally occurring fungal disease of insects that has been shown to be an effective biological control against whiteflies in cotton and vegetable crops. Six treatments were initiated in drip irrigated fall cantaloupe on October 2, and repeated on October 9 and 23. The six treatments consisted of 1) a check or unsprayed plot; 2) 0.5 lb. Mycotrol WP/acre; 3) 1 Ib. Mycotrol WP /acre; 4) 1 pt. Mycotrol ES/acre; 5) 0.5 lb. Mycotrol WP /acre + pyrethroid tank mix; and 6) 12 oz. Naturalis-L/acre. Under moderate to light sweetpotato whitefly pressure, the Mycotrol formulations provided significant control (68-79%) compared to unsprayed check plots, and were superior to Naturalis-L formulation whose effects were relatively short lived. Mycotrol WP applied in three applications at the labeled rate of 1 lb. product/acre had the cumulative effect of maintaining adult whitefly leaf counts below the currently recommended economic threshold of 3 per leaf at 28 days after treatment initiation, under the conditions of this study.

Several experimental insecticide treatment combinations were evaluated and demonstrated very good efficacy against Bemisia argentifolii [silverleaf whitefly (WF) also known as sweetpotato WF, B. tabaci]. Adults and immatures were most effectively reduced compared to the untreated check by pyriproxyfen (S-71639, Valent) treatments and fenpropathrin (Danitol®) plus acephate (Orthene®). CGA-215944 (Ciba) plus fenoxycarb (Ciba) treatments compared favorably with many of the pyrethroid combination treatments. Registered products esfenvalerate (Asana®), endosulfan (Thiodan®), cypermethrin (Ammo®), naled (Dibrom®), and oxydemeton-methyl (Metasystox-R®) complemented many of the combination treatments to reduce WF relative to the untreated check