Lesser Grain Borer

The city of Akhetaten, modern day Amarna, was founded by the monotheist pharoah Akhenaten as his new capital ca. 1353 BC, and abandoned within about 25 years. Much of the site has been excavated over the past century and few deposits remain undisturbed. In one house, however, that of the king's chief charioteer, Ranefer, rebuilding had sealed occupation debris beneath the final mud brick house floors and in the desiccating conditions of the desert, these preserved extensive insect faunas, which for the first time provide detailed data on living conditions and pest infestation in a major pharaonic urban centre. Pests of stored products include the grain weevil, Sitophilus granarius, the lesser grain borer, Rhizopertha dominica, and flour beetles, Tribolium castaneum, as well as more general pests, such as the lesser mealworm, Alphitobius diaperinus, and the biscuit beetle, Stegobium paniceum. Flies include the house fly, Musca domestica, and the puparia of a flesh fly, Sarcophagidae, burrowed vertically into the mud-brick floor in a room corner, perhaps beneath abandoned offal or meat. The taphonomy of the insect assemblages would suggest that much consisted of material dumped into the house plot, either during a phase of abandonment or to level up the area before the later house, that of Ranefer, was constructed. Trampled surfaces within the midden, often consolidated with desert sand, indicate foul damp conditions and also imply that the process was intermittent. Living conditions in the city of Akhenaten are likely not to have been as salubrious as contemporary tomb paintings might suggest.

Two natural new diatomaceous earth (DE) formulations, enhanced with abamectin (DEA-P/WP), or bitterbarkomycin (DEBBM-P/ WP), were tested under laboratory conditions against adults of the rice weevil, Sitophilus oryzae, the lesser grain borer, Rhyzopertha dominica, the red flour beetle, Tribolium castaneum and the rusty grain beetle, Cryptolestes ferrugineus. The bioassays were carried out on wheat, at 3071 1C and 7075% RH. The two enhanced DEs were applied either as dusts (P) or as wettable powders (WP) at the dose rates of 75, 100 125 and 150 ppm. Adult mortality was assessed after 14 and 21 d of exposure on the treated substrate. After this interval, the treated wheat was retained for an additional period of 49 d in the case of S. oryzae and 63 d in the case of the other three species, in order to evaluate progeny production. Generally, for all species tested, mortality was higher on wheat treated with powders in comparison with wettable solutions. After 14 d of exposure, all adults rice weevils were dead even at the lowest dose rate of DEA-P, while 100% mortality was noted at doses X125 ppm of DEBBM-P. For the other species, mortality was 100% on wheat treated with 75 ppm of DEBBM-P, with the exception of T. castaneum for which all adults were dead at doses X100 ppm. Progeny production was low, and no progeny were produced in the cases of R. dominica and C. ferrugineus, for both DEs. However, for S. oryzae, progeny production was high on wheat treated with WP formulations, at dose rates p100 ppm. Similar trends were noted for T. castaneum, at p100 ppm of DEBBM-WP. The results of the present study indicate that both DEA-P/WP and DEBBM-P/WP are more effective against the four beetle species examined in comparison with the currently commercially available DE formulations. r

Control of Rhyzopertha dominica in stored rough rice through a combination of diatomaceous earth and varietal resistance Abstract Adults of Rhyzopertha dominica (F.), the lesser grain borer, were exposed on four varieties of rough rice with Dobie indices of susceptibility of 1.1 to 1.1 (low), and four varieties with Dobie indices of susceptibility of 3.4 to 3.8 (high). The varieties with low and high Dobie indices were classified as resistant and susceptible, respectively, to R. dominica. The purpose of the study was to evaluate control of R. dominica through the use of diatomaceous earth (DE) in combination with rice varieties that were either susceptible or resistant to R. dominica. The rice was treated with varying rates of the commercial DE Insecto ® , up to a maximum of 1 000 mg DE/kg of rice. Adult mortality at each application rate of DE was generally greater on three of four resistant varieties compared to three of four susceptible varieties. Progeny production from the parental generation exposed on the rice was also greater in 3 of the 4 resistant varieties compared to 3 of the 4 susceptible varieties at DE rates of 500 mg/kg or more. Progeny production in rice treated with a maximum rate of 1 000 mg/kg DE ranged from 7-44 adults on the resistant varieties compared to 75-155 adults on the susceptible varieties. At DE rates of 500, 750, and 1 000 mg/kg, the percentage of insect-damaged kernels (IDK) was also greater in 3/4 resistant varieties than in the susceptible varieties. Results show combining the use of DE with varietal resistance of rough rice to R. dominica could be used to limit populations of this insect in stored rice and help prevent economic damage.

The city of Akhetaten, modern day Amarna, was founded by the monotheist pharoah Akhenaten as his new capital ca. 1353 BC, and abandoned within about 25 years. Much of the site has been excavated over the past century and few deposits remain undisturbed. In one house, however, that of the king's chief charioteer, Ranefer, rebuilding had sealed occupation debris beneath the final mud brick house floors and in the desiccating conditions of the desert, these preserved extensive insect faunas, which for the first time provide detailed data on living conditions and pest infestation in a major pharaonic urban centre. Pests of stored products include the grain weevil, Sitophilus granarius, the lesser grain borer, Rhizopertha dominica, and flour beetles, Tribolium castaneum, as well as more general pests, such as the lesser mealworm, Alphitobius diaperinus, and the biscuit beetle, Stegobium paniceum. Flies include the house fly, Musca domestica, and the puparia of a flesh fly, Sarcophagidae, burrowed vertically into the mud-brick floor in a room corner, perhaps beneath abandoned offal or meat. The taphonomy of the insect assemblages would suggest that much consisted of material dumped into the house plot, either during a phase of abandonment or to level up the area before the later house, that of Ranefer, was constructed. Trampled surfaces within the midden, often consolidated with desert sand, indicate foul damp conditions and also imply that the process was intermittent. Living conditions in the city of Akhenaten are likely not to have been as salubrious as contemporary tomb paintings might suggest.

Although high concentrations of zinc and manganese were found in mandibles of insect larvae that bore into seeds, these metals were not detected in mandibles of insect larvae that attack previously damaged seeds. Metals were present in the larval mandibles of a lepidopteran, the Angoumois grain moth (Sitotroga cerealella), and eight coleopterans, the lesser grain borer (Rhyzopertha dominica), cigarette beetle (Lasioderma serricorne), drugstore beetle (Stegobium paniceum), spider beetle (Gibbium aequinoctiale), warehouse beetle (Trogoderma variabile), cadelle (Tenebroides mauritanicus), larger black flour beetle (Cynaeus angustus), and cowpea weevil (Callosobruchus maculatus). Larvae of these species can chew into seeds. Larvae of six other coleopterans, the varied carpet beetle (Anthrenus verbasci), sawtoothed grain beetle (Oryzaephilus surinamensis), rusty grain beetle (Cryptolestes ferrugineus), red flour beetle (Tribolium castaneum), longheaded flour beetle (Latheticus oryzae), and granary weevil (Sitophilus granarius) have little if any ability to chew into seeds, and did not have metal in their mandibles. Larvae of the granary weevil hatch and feed within seeds that were penetrated previously during egg deposition by adults. However, newly hatched larvae of the cowpea weevil and the Angoumois grain moth have to bore through the seed coat before they begin feeding, and they have mandibles with high concentrations of zinc. These data support the hypothesis that deposition of zinc and/or manganese in larval mandibles enhances the larva's ability to penetrate seeds. Published by Elsevier Science Ltd.

We determined that the number of insect fragments, quantiÞed using the standard ßotation method, in ßour milled from wheat infested with larvae, pupae, or preemergent adults of the lesser grain borer, Rhyzopertha dominica (F.), was proportional to infestation level. Wheat infested with a single preemergent adult contributed 28 and 10ϫ as many fragments as wheat infested with a single larva or pupa, respectively. Using regression models that were developed from these data, we predicted that the maximum infestation level that would result in ßour with fragment counts below the Food and Drug Administration defect action level (75 fragments/50 g of ßour) was 0.95 and 1.5% (380 Ð 640 infested kernels/kg of wheat) for pupae and larvae, but it decreased to 0.05% (20 infested kernels/kg) when the grain was infested with preemergent adults. We also reexamined the accuracy and sensitivity of near-infrared spectroscopy (NIRS) for detecting insect fragments in ßour by testing three different NIR spectrometers. NIRS-predicted numbers of insect fragments were correlated with the actual number of fragments. NIRS is less precise than the standard ßotation method, but it is rapid, nondestructive, does not require extensive sample preparation, and could easily be automated for a more sophisticated sampling protocol for ßour based on prescreening samples with NIRS followed up by use of the standard ßotation method when necessary.

This report provides further evidence that a fi'eeze-dried, concentrated form of Pseudomonas sgringae, an ice-nucleating active bacteria, reduces the cold tolerance of stored grain insect pests. Application of ice-nucleating bacteria to wheat or corn that contained insect pests decreased the insects' supercooling capacity: after treatment with 100 ppm of P. sqringae the mean supercooling points of five insect species increased from 4.7 to ll.9'C above untreated controls. Treatment with P. syringae also decreased the capacity of insects to survive a 24-h exposure to subzero temperatules. Decreases in eold tolerance were observed in eight species of stored grain pests: Indianmeal moth larvae, Plodia interpunctellu (Htibner); red flotir beetle adults, Tribolium castaneun'L (Herbst); fiat grain beetle adults, Crgptolestes pusillus (Schonherr); rusty grain beetle adults, Crgptolestes ferrugineus (Stephens) ; Cibbium psVlloides (Czenpinski); lesser grain borer adults, Rhgzopertha dominica (F.); yellow mealworm lawae, Tenebri,o molitor (L.); and granary weevil adults, Sitophilus granarius (L.). Results ofthis study provide further support for the use of ice-nucleating active bacteria as biological insecticides to kill overwintering insects by decreasing their low temperature tolerance. The approach may be particularly appropdate for the control ofa variety ofinsect pests in lestricted areas such as grain bins. KEY WORDS Insecta, cold-hardiness, ice nucleating bacteria, biological control 0O22-04931C21O371-0374$02.00/0 O 1992 Entomolosical Society of America ]ounNer. or EcoNolrrc ENrouor,ocY Vol. 85, no. 2

The flight activity of lesser grain borer, Rhyzopertha dominica F. (Coleoptera: Bostrichidae), was monitored at two Foundation seed wheat warehouses during the 2003 and 2004 field seasons, using pheromone-baited Lindgren funnel traps positioned indoors and outdoors. General stored-product insect activity was also monitored using unbaited sticky traps positioned inside the warehouses around overhead doors. Pheromone-baited traps were useful for monitoring R. dominica activity, however insect captures decreased when lures were not changed weekly. Flight peaks were documented in early May and again from September through October, and insect captures inside warehouses correlated with timing of outdoor captures. Multiple regression analyses showed that slightly more than half of the variability in R. dominica captures could be explained by mean ambient air temperature and wind speed during the 2 h preceding sunset. Stored-product Coleoptera captured on unbaited glue boards around overhead doors included Ahasverus advena, Cryptolestes ferrugineus, R. dominica, Sitophilus oryzae, Tribolium castaneum , Trogoderma variabile , and Typhaea stercorea. Door gaskets significantly reduced the number of insect captures on glue boards placed around the overhead doors, and generally restricted their entry to ground level. These studies demonstrated that outdoor pheromone-baited traps are effective monitoring tools for determining when grain-handling facilities are most susceptible to infestation and that exclusion may be an effective component of a pest management program.

Wheat kernels infested internally with larvae of 3 primary insect pests of grain, the rice weevil, Sitophilus oryzae (L.); the lesser grain borer, Hhgzoperthn dominica (F'); and the Angoumois grain moth, Sitotroga cereaLelln (Olivier), were scanned with a near-infrared spectrom- etei incorpoiated into a single kernel characterization system to determine differences in absorption due to th! p."s"n"e of larvae. The

We determined that the number of insect fragments, quantiÞed using the standard ßotation method, in ßour milled from wheat infested with larvae, pupae, or preemergent adults of the lesser grain borer, Rhyzopertha dominica (F.), was proportional to infestation level. Wheat infested with a single preemergent adult contributed 28 and 10ϫ as many fragments as wheat infested with a single larva or pupa, respectively. Using regression models that were developed from these data, we predicted that the maximum infestation level that would result in ßour with fragment counts below the Food and Drug Administration defect action level (75 fragments/50 g of ßour) was 0.95 and 1.5% (380 Ð 640 infested kernels/kg of wheat) for pupae and larvae, but it decreased to 0.05% (20 infested kernels/kg) when the grain was infested with preemergent adults. We also reexamined the accuracy and sensitivity of near-infrared spectroscopy (NIRS) for detecting insect fragments in ßour by testing three different NIR spectrometers. NIRS-predicted numbers of insect fragments were correlated with the actual number of fragments. NIRS is less precise than the standard ßotation method, but it is rapid, nondestructive, does not require extensive sample preparation, and could easily be automated for a more sophisticated sampling protocol for ßour based on prescreening samples with NIRS followed up by use of the standard ßotation method when necessary.

The accuracy of near-infrared spectroscopy (NIRS) for predicting the chronological age of adults of the rice weevil, Sitophilus oryzae (L.); the lesser grain borer, Rhyzopertha dominica (F.); and the red ßour beetle, Tribolium castaneum (Herbst), three pests of stored grain, was examined. NIRS-predicted age correlated well with actual age of these three species. Age predictions in S. oryzae by using the NIRS method are not dependent upon adult sex or temperatures to which adult weevils are exposed. Results indicated that water content decreased with increasing age in rice weevil adults, and excluding wavelengths at which water absorbs NIR radiation reduced the accuracy of correct classiÞcation. Additionally, removing cuticular lipids from insects resulted in a signiÞcant decrease in classiÞcation accuracy of weevils, indicating that these compounds may be partly responsible for the ability of NIRS to differentiate young from old beetles. NIRS is a nondestructive technique that can be used to age-grade large numbers of adult stored-product beetles, information that could help to increase the accuracy of population models for these pest species.

Effects of crowding, food deprivation, and type of cereal diet upon flight initiation, development, body weight, lipid content, and fatty acid composition of the lesser grain borer, Rhyzopertha dominica (F.), were studied in two field strains and one laboratory strain. Beetles of all strains reared under crowded conditions had significantly higher flight initiation than beetles reared on isolated kernels (uncrowded). Regardless of degree of crowding, flight initiation increased with the period of food deprivation up to a maximum at 24 h, after which flight initiation declined. Body weight and lipid content decreased as the food deprivation period increased, whereas fatty acid composition was not significantly affected by food deprivation. Beetles from a field strain collected in 1995 had higher flight initiation and increased lipid content compared with beetles from the laboratory strain. However, beetles from the laboratory strain were larger, developed faster, and were more fecund than beetles from this field strain. The cereal diet on which beetles were reared also had a significant effect on flight initiation, lipid content, and fatty acid composition. Beetles reared on whole rice and wheat produced adults with higher flight initiation, higher lipid content, and higher oleic acid concentration than beetles reared on whole corn and sorghum.