Incidencia del parasitoide Calliephialtes grapholithae Cresson (Hymenoptera: Ichneumonidae) en larvas de Cydia caryana Fitch (Lepidoptera: Tortricidae)

Se reporta la asociación entre el parasitoide Calliephialtes grapholithae y la larva de Cydia caryana. Se colectaron nueces pecaneras en el área de Jaumave, Tamaulipas, después las frutas fueron confinadas en cajas plásticas para esperar la emergencia de los adultos. Otro himenóptero que emergió durante el estudio fue Eupelmus sp.; sin embargo, su asociación no puede ser confirmada debido a que podría comportarse como parasitoide o hiperparasitoide.

Micobiota y Metarhizium asilados de larvas del gusano barrenador del ruezno (Cydia caryana)

La necesidad de contar con organismos nativos con potencial para el control biológico de plagas para el nogal pecanero, motivaron el registro de la micobiota y búsqueda de entomopatógenos en larvas del gusano barrenador del ruezno (GBR) Cydia caryana. Para ello, en el año 2013, en una huerta de nogal en La Laguna México, se recolectaron y procesaron 5 000 rueznos para extraer larvas de GBR, que fueron incubadas en cámara húmeda o suelo. De larvas obtenidas antes del 12 de septiembre y colocadas en suelo se recobró 9% de Fusarium spp. + Gliocladium spp., en contraste, ambos hongos aparecieron 40% en larvas obtenidas después de esa fecha. En larvas obtenidas en diciembre y se colocaron en cámara húmeda, Fusarium + Gliocladium spp. aparecieron 80%. Únicamente fue evidentemente a Metarhizium anisopliae como entomopatógenos de 5% de larvas del GBR colocadas en suelo después del 12 de septiembre, éste hongo también fue entomopatógenos del ácaro rojo gigante Trombidium sp., pulgón negro del nogal Melanocallis caryaefoliae, Garrapata Rhipicephalus sanguineus, y hormiga roja Solenopsis sp. Larvas de GBR pueden usarse como trampa para recobrar Metarhizium y probablemente otros hongos entomopatógenos en suelo de huertas de nogal pecanero.

Insect Damage Estimates for ‘Stuart’ Pecan Nutlets from Nut Set to Shell Hardening in Insecticide-Treated and Untreated Trees

Pecan nut loss due to pecan nut casebearer, Acrobasis nuxvorella Neunzig, damage was significantly lower in the chlorpyrifos-treated, ‘Stuart’, pecan trees (0%) than in untreated trees (16%). Percentage loss due to nut drop from all causes between nut set and shell-hardening was significantly lower in the treated (27%) than in the untreated trees (42%). Treated trees had significantly higher average yield (38 kg/tree) than the untreated (29 kg/tree). Nut size was significantly smaller in untreated (156 nuts/kg) than in treated trees (145 nuts/kg). Monitoring the fate of ‘Stuart’ pecan nutlets from nut set to harvest indicated that the number of nuts/cluster at nut set was often positively correlated with kernel weight at harvest, whereas, nut cluster size later in the season was positively correlated with kernel weight at two orchards and negatively correlated with kernel weight in the control treatment at a third orchard. A commercial orchard where pecan nut casebearer, hickory shuckworm, Cydia caryana (Fitch) and nut curculio, Conatrachelus hicoriae Schoof, were controlled with insecticide sprays in the spring had similar total nut drop over the entire season as an orchard where these insects were not controlled. The majority of the pecans that dropped from the trees did not have discernible signs of plant disease, insect feeding damage or insect oviposition.

Cold Tolerance of Hickory Shuckworm (Lepidoptera: Tortricidae) Larvae and Associated Parasites

Hickory shuckworm larvae, Cydia caryana (Fitch), in pecan shucks, were killed by extended periods of freezing temperature. While storage at −7°C killed 88% of larvae after 32 days of exposure, −18°C killed 85% after only 1 day and 100% by 8 to 16 days of exposure. Larvae exposed to cold temperatures prior to −18°C exposure appeared to possess enhanced cold resistance but were still killed after 32 days of exposure. Survival of the ichneumonid parasite, Calliephialtes grapholithae (Cresson), which comprised 92% of the total of all parasites emerging from pecan shucks, was not detectably affected by exposure to cooling (3–5°C) for up to 5 wks. Thereafter, when emergence began to decrease, about half of the parasites in the extended cooling treatment were viable for at least 10 wks. Conversely, 3 other parasites Phanerotoma fasciata Provancher (Braconidae), Macrocentrus instabilis Muesebeck (Braconidae), and Lixophaga mediocris Aldrich (Tachinidae), comprised the remaining 8% of total parasite emergence and survival was severely affected by extended cooling (3–5°C).

Effects of Pheromone Trap Design and Placement on Capture of Male Cydia caryana (Lepidoptera: Tortricidae: Olethreutinae) in Alabama Pecan Orchards and the Relationship of Trap Captures to Fruit Infestation

The Pherocon Ic trap captured the greatest number of Cydia caryana (Fitch) adult males and all trap designs appeared to represent population trends equally well. Pooled data from all trap height experiments indicate that traps placed 9.14 m above the orchard floor captured significantly more adult males than those placed at 4.57 m height. Horizontal placement of traps within the tree canopy indicated a significantly greater capture in the central portion of the canopy than at other locations. Correlations between the total capture of male adults and the rate of fruit infestation were not significant.

Adult Emergence Patterns, Population Trends and Activity Patterns of the Hickory Shuckworm, Cydia caryana (Lepidoptera: Tortricidae: Olethreutinae) in Pecan Orchards

Emergence of hickory shuckworm, Cydia caryana (Fitch), adults from larval overwintering sites was bimodal. The major emergence peak occurred during the period of mid-March to mid-May and the smaller activity period during July and August. Pheromone trapping was effective for monitoring population trends during generations 1 and 5 of C. caryana but less so during generations 2, 3, and 4. Activity patterns suggest the species is crepuscular rather than truly nocturnal.

A Scanning Electron Microscope study of the pecan phylloxera, Phylloxera devastatrix, with observations on emergence

The pecan phylloxera, Phylloxera devastatrix Pergande, is a small, cecidogenic insect found throughout the native range of the pecan tree. Infestations of P. devastatrix have been reported to cause reductions in nut quality and quantity, premature defoliation, and shoot dieback. Galls formed by P. devastatrix are an alternate host for the larvae of the hickory shuckworm, Cydia caryana Fitch. Little information exists on the biology and ecology of this insect. The objective of this study was to examine the emergence patterns of P. devastatrix on different pecan cultivars to determine if variability in bud-break between cultivars effected emergence. This study also provided an opportunity to study gall formation and the life cycle in detail.P. devastatrix overwinter as an egg within the body of the sexual female (Figs. 1 & 2). Upon hatching, the stem mother moves to the bud and begins feeding (Figs. 3 & 4). As the stem mother feeds, a gall begins to form around the insect (Fig. 3). Eggs deposited within the gall by the mature stem mother (Fig. 6) hatch into apterous and alate females (Fig. 7). Eggs produced by these females hatch into sexual males and females (Fig. 8 & 9). After mating, an egg is produced within the body of the female. The female next seeks a place on the tree to overwinter, thus completing the cycle. Stoetzel described the development of the stem mother and apterous and alate females as hemimetabolous (incomplete metamorphosis), and that of the sexual males and females as holometabolous (complete metamorphosis). Gal1s of p. devastatrix are classified as cover galls. The upwalling of the plant tissue around the insect, characteristic of this type of gall, can be clearly seen in the SEM photographs (Figs. 3 & 5).