The toxicity and sublethal effects of methoxyfenozide were evaluated in third instars of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera:

To determine the natural parasitism in fruit fly populations in disturbed areas adjacent to commercial mango orchards in the states of Chiapas and Veracruz, Mexico, we recorded over one year the fruit fly–host associations, fly infestation, and parasitism rates in backyard orchards and patches of native vegetation. We also investigated the relationship between fruit size, level of larval infestation, and percent of parasitism, and attempted to determine the presence of superparasitism. The most recurrent species in trap catches was Anastrepha obliqua (Macquart), followed by Anastrepha ludens (Loew), in both study zones. The fruit infestation rates were higher in Chiapas than in Veracruz, with A. obliqua again being the most conspicuous species emerging from collected fruits. The diversity of parasitoids species attacking fruit fly larvae was greater in Chiapas, with a predominance of Doryctobracon areolatus (Szépligeti) in both sites, although the exotic Diachasmimorpha longicaudata (Ashmead) was well established in Chiapas. Fruit size was positively correlated with the number of larvae per fruit, but this relationship was not observed in the level of parasitism. The number of oviposition scars was not related to the number of immature parasitoids inside the pupa of D. areolatus emerging from plum fruits. Mass releases of Di. longicaudata seem not to affect the presence or prevalence of the native species. Our findings open new research scenarios on the role and impact of native parasitoid species attacking Anastrepha flies that can contribute to the development of sound strategies for using these species in projects for augmentative biological control.

The effects of 2 concentrations (15 and 30%) of ethanolic Argemone ochroleuca Sweet (Papaveraceae) extracts were determined on the feeding behavior and development of 3rd instar larvae of the fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) through their continuous ingestion of treated maize leaves for 48 h. The extracts were obtained from dried whole plants including stems, leaves, and flowers. Armyworm food consumption was slightly reduced (by 13 to 14%) at both concentrations compared with the controls. Larval growth was significantly affected only at the highest concentration, with a 23% reduction in larval weight after 48 h of feeding on the treated leaves and a 38% reduction after another 48 h of feeding on an untreated artificial diet. By contrast, the duration of the larval and pupal stages was prolonged by 43% (from 13.5 to 19.4 d) and by 8% (from 2.1 to 2.2 d), respectively. Total larval mortality was also higher at the highest concentration (31%) than in cont... Resumen En este estudio se determinó, a través de la ingestión continua de hojas tratadas de maíz durante 48 h, el efecto de dos concentraciones (15% y 30%) de extractos etanólicos de Argemone ochroleuca Sweet (Papaveraceae) sobre el comportamiento de alimentación y desarrollo de larvas de tercer ínstar del gusano cogollero, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae). Los extractos se obtuvieron de plantas completas secas incluyendo tallos, hojas y flores. El consumo de alimento se redujo ligeramente (en 13 a 14%) en ambas concentraciones comparado con el testigo. El crecimiento fue afectado significativamente solamente en la más alta concentración, con una reducción de 23% del peso larval después de 48 h de alimentación sobre las hojas tratadas y un 38% de reducción después de otras 48 h de alimentación sobre dieta artificial no tratada. En contraste, la duración de los estados de larva y pupa se incrementó en 43% (desde 13.5 a 19.4 d) y 8% (desde 2.1 a 2.2. d), respectivamente. La mort...

This study describes four multiple nucleocapsid nucleopolyhedrovirus isolates recovered from infected larvae of beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), on crops in two different geographical regions of Mexico. Molecular and biological characterization was compared with characterized S. exigua multiple nucleopolyhedrovirus (SeMNPV) isolates from the United States (SeUS1 and SeUS2) and Spain (SeSP2). Restriction endonuclease analysis of viral DNA confirmed that all Mexican isolates were SeMNPV isolates, but molecular differences between the Mexican and the reference isolates were detected using PCR combined with restriction fragment length polymorphism (RFLP). Amplification of the variable region V01 combined with RFLP distinguished the two Mexican isolates, SeSLP6 and SeSIN6. BglII digestions showed that the majority of the isolates contained submolar bands, indicating the presence of genetic heterogeneity. Amplification of the variable regions V04 and V05 distinguished between American and the Spanish isolates. Biological characterization was performed against two laboratory colonies of S. exigua, one from Mexico, and another from Switzerland. Insects from the Mexican colony were less susceptible to infection than insects from Se-Swiss colony. In the Se-Mex colony, SeSP2 was the most pathogenic isolate followed by SeSIN6, although their virulence was similar to most of the isolates tested. In Se-Swiss colony, similar LD₅₀ values were observed for the five isolates, although the virulence was higher for the SeSLP6 isolate, which also had the highest OB (occlusion body) yield. We conclude that the Mexican isolates SeSIN6 and SeSLP6 possess insecticidal traits of value for the development of biopesticides for the control of populations of S. exigua.

The life cycle and several life parameters of the zoophytophagous predator Engytatus varians (Distant) (Heteroptera: Miridae), including nymphal growth according to Dyar’s rule, were examined in the laboratory. The egg, nymph (five instars), and adult stages were 9.20, 17.36, and 19.02 d in length, respectively. The growth ratio for nymphs was consistent with Dyar’s rule based on the lengths of the femora of the forelegs, the tibiae and femora of the middle legs, and the antennae. Some biological characteristics of E. varians were also evaluated when the mirid was fed three different diets (B. cockerelli third instars, Sitotroga cerealella Olivier [Lepidoptera: Gelechiidae] eggs, and a mixture of both instars and eggs). The length of the nymphal stage was three days longer on a diet of only S. cerealella eggs than when the mirids were fed the third instars of B. cockerelli only or a mixture of both. The sex ratio was not affected by the type of diet. Nymphs of E. varians consumed B. cockerelli nymphs (80–85) when fed third instars only and third instars + S. cerealella eggs, respectively. The potential use of this predator as a biological control agent of B. cockerelli is discussed.