John H. Brower

Suppression of residual populations of stored-product pests in empty corn bins by releasing the predator Xylocoris flavipes (Reuter)

Populations of stored grain pests infesting grain residues in empty corn bins were affected differently by releases of 50 pairs of the predatory warehouse pirate bug, Xylocoris flavipes (Reuter) (Hemiptera: Anthocoridae). Large insects, such as late instar pyralid moth larvae and adults, apparently were unaffected by the releases. Also, species such as the Sitophilus weevils and the lesser grain borer that develop in grain kernels were much less affected than small externally feeding insects. However, populations of a wide variety of species of small beetles, including both direct grain feeders (Tribolium castaneum, Oryzaephilus surinamensis, and Cryptolestes spp.) and secondary feeders (Ahasverus advena, Typhaea stericorea, and Carpophilus dimidiatus were either greatly reduced or eliminated by X. flavipes. Populations of these species had been reduced by 70 to 100% at the termination of the tests. Our results showed that residual populations of several species of small beetles in empty grain bins can be greatly reduced by weekly releases of a small number of X. flavipes. If specific parasitoids for moths and the primary grain pests were also released, the whole pest complex inhabiting empty grain bins might be greatly reduced or eliminated before newly harvested grain is brought to the bins for storage.

Effects of Xylocoris flavipes (Hemiptera: Anthocoridae) Releases on Moth Populations in Experimental Peanut Storages

A biological control test in experimental peanut storages indicated that release of large numbers of the warehouse pirate bug, Xylocoris flavipes (Reuter) (Hemiptera: Anthocoridae), a generalist predator of stored-product insects, has considerable potential for suppression of stored-product moth populations. Suppression of the almond moth, Cadra cautella (Walker), and the Indianmeal moth, Plodia interpunctella (Hubner) (Lepidoptera: Pyralidae), was dependent on both the prey species and environmental conditions. Release of X. flavipes suppressed small populations of almond and Indianmeal moths by as much as 78.8% and 71.4%, respectively, before cold weather and a severe freeze eliminated the almond moth population in January. Suppression of the Indianmeal moth lasted through the 7-month test period. X. flavipes may be useful as one component of an integrated peanut control program based on release of biological agents

INTERACTIONS BETWEEN THE EGG PARASITE TRICHOGRAMMA PRETIOSUM (HYMENOPTERA: TRICHOGRAMMATIDAE) AND A PREDATOR, XYLOCORIS FLAVIPES, (HEMIPTERA: ANTHOCORIDAE) OF THE ALMOND MOTH, CADRA CAUTELLA, (LEPIDOPTERA: PYRALIDAE)

Tests were conducted to determine interspecific interactions between an egg parasite, Trichogramma pretiosum (Riley), and a general predator, Xylocoris flavipes (Reuter), of the almond moth, Cadra ...

Comparative gamma radiation sensitivity of Tribolium madens (Charpentier) and T. castaneum (Herbst)

Abstract The effects of gamma radiation doses between 5 and 100 krad on all metamorphic stages of Tribolium madens and T. castaneum were studied. Results from the two species were similar although T. madens appeared to be more radiosensitive. The development of adults from treated eggs and larvae was prevented by 5 krad in T. madens and by 10 krad in T. castaneum. Some adults emerged from treated pupae at all treatment levels, but no reproduction occurred at 20 krad or above. Adult females of both species were more sensitive to the sterilizing effects of gamma radiation than were males, but sterility of both sexes was effected at doses of 30 krad and above. Control of these two species appears feasible with levels of radiation currently approved for treatment of stored-grain insects in wheat and wheat flour.

Potential for control of Cadra cautella (Walker) by release of fully or partially sterile males

Modifications of the sterile-male release technique appear to offer promise for the control of post-harvest lepidopteran pest populations within storage structures. Theoretical models of release strategies for Cadra cautella (Walker) showed that each method has an “ideal” flooding ratio. This ratio represents the best balance between extinction in a few generations and minimization of the total number of insects released. From data reported concerning the population dynamics of Cadra cautella in the field an ideal flooding ratio for fully sterile (S) males to fertile (F) males of 97:1 would achieve extinction in 3 generations. The ratio of partially sterile males released in alternate generations that would achieve extinction in 4 generations was 125:1, and the ratio of partially sterile males released every generation that would achieve extinction in 5 generations was 74:1. Total numbers of males released per 100 native insects (♂ + ♀) that would be needed to achieve extinction at these flooding ratios would be 14,850, 14,900 and 18,500, respectively.

Effects of gamma radiation on the larval midgut of the Indian-meal moth, Plodia interpunctella (Lepidoptera: Phycitidae).

The normal midgut consisted of an epithelial layer, a thin basement membrane, an inner circular muscle coat, and outer bundles of longitudinal muscles. The major cytological damage associated with radiation exposure was displayed by the midgut epithelium. Damage ranged from moderate cell disruption 4 days after treatment with 5 krads to almost complete histolysis following 50 krads. The regenerative cells that renew the epithelial lining of the midgut were particularly sensitive to radiation damage resulting in an inability to replace the midgut epithelium.

Insect control in wheat flour with gamma irradiation

Abstract When commercially produced, bleached, and enriched wheat flour was artificially infested with insects, packed in metal cans or multiwall paper bags, and irradiated with ca . 40 krad in a 60 Co gamma irradiator, insects of all species were present one month later but in much smaller numbers than in the controls. After 3–14 months, no living insects were found in the irradiated flour, and healthy populations were present in the untreated flour. Thus control of insect species in flour can be achieved by doses of ca . 40 krad, but death of the older stages is not immediate.

Suppression of Sitotroga cerealella in shelled corn by the parasitoid Pteromalus cerealella

The parasitoid Pteromalus cerealellae (Ashmead) was introduced at densities of one, five, or 10 pairs into 0.47-liter jars containing 500 g of corn that had been infested with one, five or 10 pairs of the Angoumois grain moth, Sitotroga cerealella (Olivier), adults. The abundance of S. cerealella progeny was significantly reduced by all release rates of parasitoids and at all densities of S. cerealella. As release rates increased from one to 10 pairs of P. cerealellae, the average percentage suppression increased from 85.5 to 99.2 at one pair of S. cerealella, from 77.2 to 98.0 at five pairs of S. cerealella, and from 66.9 to 95.8 at 10 pairs of S. cerealella. However, the degree of suppression was significantly influenced by both the numbers of P. cerealella released and the initial density of S. cerealella. With greater host density, more progeny of P. cerealellae were produced, but releasing more parasitoids did not significantly increase the number of P. cerealellae progeny.

Reduction of malathion resistance in caged almond moth, Cadra cautella (Walker) (Lepidoptera: Pyralidae), populations by the introduction of susceptible males☆

Abstract Caged populations of the almond moth, Cadra cautella (Walker), that were resistant to malathion were subjected to the release of susceptible males at various ratios. The effects of introducing malathion susceptible males into the population were monitored by determining the LD50s for 21 day old larvae from each population. F1 hybrid larvae were found to be intermediate in resistance between larvae from the parental strains, and resistance appeared to be inherited in a codominant fashion. Populations which received only a single release of males were, in general, more malathion susceptible the greater the introduction ratio (except at a ratio of 20:1). Larger populations subjected to repeated introductions of susceptible males showed a clear trend of decreasing larval survival after malathion treatment with increasing release ratio (including the 20:1 ratio). These results indicated that desirable alleles, such as those for insecticide susceptibility, can be introduced into established populations, and that this line of research should be given more emphasis in preventing development of resistance or in ameliorating established resistance.

Effects of Irradiated Diets on Production of Progeny by Several Successive Generations of the Indian-Meal Moth, Plodia interpunctella (Hübner)

Indian meal moths, Plodia interpunctella, were reared for nine generations on an irradiated whole wheat flour diet or for four generations on irradiated raisins. Diets were treated with dosages of 0, 25, 50, 100, 500, 1000, and 4300 krad of gamma radiation. Each generation was checked for fecundity and for altered sex ratios. No statistically or biologically significant effects on the numbers of progeny or their sex ratio were found. Irradiated flour and raisins appear to be safe as insect culture media.