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The black squash mirid, Pycnoderes quadrimaculatusGuérin-Méneville, 1857, was recently found feeding on chayote squash, Sechium edule (Jacq.) Sw. (Cucurbitaceae), under cultivation in Campo Grande, Veracruz, Mexico. Based on the economic importance of this plant in the region, research under laboratory conditions was initiated to study essential aspects of the biology (duration of life cycle and survival) and basic morphology of this pest insect. The duration of the egg, immature (instars 1—5), and adult stages lasted 14.2, 14.1, and 31 days, respectively. Elongated, slightly curved eggs, without respiratory projections, were inserted in the main and secondary veins of chayote leaves. All nymphal instars were yellowish to pale greenish with distinct black regions and black setae scattered over the dorsum, except for the hyaline to whitish and smooth first instar. Sexual dimorphism was not present in P. quadrimaculatus. The probability of survival for males and females feeding on chayote squash was estimated to be 100% at 3 and 21 days, respectively. Subsequently, survival decreased without significant differences between the sexes. This is the first report of aspects of the life cycle, morphology, and survival of P. quadrimaculatus. [ABSTRACT FROM AUTHOR]

BACKGROUND Control of the Asian citrus psyllid Diaphorina citri Kuwayama, the most important pest of citrus worldwide, is based on the use of insecticides, though unsatisfactory results have recently been reported. In this study, insecticide resistance of D. citri to three insecticides (bifenthrin, malathion, and chlorpyrifos) was examined. RESULTS Three populations (designated Dci-CParácuaro, Dci-El Junco, and Dci-Antúnez) of both adults and fourth-instar D. citri individuals were collected in 2014 at two different times and on one occasion, respectively, from three locations (Crucero de Parácuaro, El Junco, and Antúnez). These locations represent the major commercial Mexican lemon production areas in the Apatzingán Valley in the state of Michoacán, Mexico. The three populations of D. citri adults and fourth-instar nymphs at the different collection times showed low levels of resistance (≤7-fold) to bifenthrin, but were very resistant to malathion (≤345- and ≤432-fold for adults and fourth instars, respectively) and chlorpyrifos (≤2435- and ≤1424-fold for adults and fourth instars, respectively). CONCLUSION Resistance levels to the tested insecticides were highly variable but homogeneous among seasons and localities. Resistance management programmes that include crop sanitation, use of biological and cultural control practices, and rotation of insecticide classes should be established, particularly in areas where D. citri has developed resistance to malathion and chlorpyrifos. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The toxicity and sublethal effects of methoxyfenozide were evaluated in third instars of the beet armyworm, Spodoptera exigua (Hubner) (Lepidoptera: Noctuidae), that fed on contaminated semisynthetic diet. The LC50 value was estimated at 0.23 mg of active ingredient (Al) 1kg diet (range, 95% CI: 0.17–0.37) at 264 h after treatment. The effects on development, survival, and reproduction were observed in third instars of this pest that survived exposure to an LC25 concentration of methoxyfenozide. The larvae from the insecticide treatment exhibited lower pupal weights, an increase in both larval and pupal developmental times and a higher frequency of malformations of the wings in adults than untreated larvae. Adults from the methoxyfenozide treatment did not show reduced fecundity (mean cumulative number of eggs laid per female), but fertility as measured by the percentage of eggs hatched (fertility) was significantly reduced compared with untreated control insects. No significant effects were observed on pupal sex ratio. We concluded that the lethal and sublethal effects of methoxyfenozide are likely to have a significant impact on S. exigua populations on treated crops. [ABSTRACT FROM AUTHOR]