Indianmeal Moth Populations Research Articles

A Computer Model for Simulating Population Development of the Indianmeal Moth (Lepidoptera: Pyralidae) in Stored Corn

The Indianmeal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), is a common pest of stored corn, Zea mays L. We developed a computer model to simulate population development of the Indianmeal moth in stored corn by using previously published data describing immature developmental times and survivorship, and adult longevity and fecundity. The model accurately simulated population development of Indianmeal moths in corn stored during fall and into winter of three separate storage seasons in South Carolina. This is the period when the Indianmeal moth is a pest in stored corn in South Carolina. The model predicted that populations would increase after winter as grain temperatures rose, but observed populations in the grain bins never increased after winter. Despite this, the model should be useful from a management perspective because the corn is being sold off or used up after winter, and the observed Indianmeal moth populations never reached damaging levels after winter.

Ovipositional preferences and larval performances of two populations of Indianmeal moth, Plodia interpunctella

AbstractOviposition decisions by female insects can determine the survival and fitness of their offspring. In this study, we assessed the larval performance and adult oviposition preferences of two populations of the Indianmeal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), one a long‐term laboratory colony and another recently collected from the field. Development assays on a variety of foods were conducted on individual larvae in small shell vials, and data were collected for survival (percent), development time (days), and adult weight (mg). Larvae from both populations did not survive on ground walnut, pecan, coriander, and fennel. There were significant differences in larval survival on laboratory diet, chick pea, and soybean between the two populations. Development times were the longest on prunes and barley. Mean adult weights were the highest on chick pea, laboratory diet, and soybean for the laboratory moths whereas soybean and chick pea were very suitable for the field moths. Overall, field moths weighed significantly less than the laboratory moths. Adult ovipositional preferences were assessed in no‐choice and four‐choice oviposition bioassays in plastic boxes containing diets differing in quality. In a no‐choice situation, the numbers of eggs laid by laboratory moths on soybean, apricots, and wheat were not significantly different. Field moths laid significantly greater numbers of eggs on soybean, and those numbers were similar to those laid on barley. In four‐choice bioassays, laboratory moths oviposited in diets previously determined to be unsuitable for their progeny survival. Field moths were more selective and laid significantly greater numbers of eggs on soybean than in dishes containing barley, coriander, or an empty dish. Our studies clearly showed that laboratory colonization of Plodia interpunctella for long periods can alter the behavioral patterns of immatures and adults.

Integration of nonchemical treatments for control of postharvest pyralid moths (Lepidoptera: Pyralidae) in almonds and raisins.

We propose a treatment strategy combining an initial disinfestation treatment with one of three protective treatments as an alternative for chemical fumigation of almonds and raisins for control of postharvest insect populations. Initial disinfestation treatments using low oxygen controlled atmosphere (0.4% O2) were designed to disinfest product of field populations of pyralid moths; navel orangeworm, Amyelois transitella (Walker), in almonds and raisin moth, Cadra figulilella (Gregson), in raisins. The protective treatments were cold storage (10 degrees C), controlled atmosphere (5% O2) storage, and application of the Indianmeal moth granulosis virus, and were designed to prevent establishment of Indianmeal moth, Plodia interpunctella (Hübner). The initial disinfestation treatment was effective against laboratory populations of navel orangeworm and raisin moth. Efficacy of protective treatments was determined by exposure of commodities to laboratory Indianmeal moth populations at levels far higher than those found in commercial storage facilities. All three protective treatments prevented development of damaging Indianmeal moth populations as measured by pheromone trap catches and evaluation of product samples. Quality analysis by commercial laboratories showed that overall product quality for all protective treatments was maintained at levels acceptable by industry standards.

Life History Attributes of Indian Meal Moth (Lepidoptera: Pyralidae) and Angoumois Grain Moth (Lepidoptera: Gelechiidae) Reared on Transgenic Corn Kernels

The Indian meal moth, Plodia interpunctella (Hübner), and Angoumois grain moth, Sitotroga cerealella (Olivier), are two globally distributed stored-grain pests. Laboratory experiments were conducted to examine the impact that corn (Zea mays L.) kernels (i.e., grain) of some Bacillus thuringiensis Berliner (Bt) corn hybrids containing CrylAb Bt delta-endotoxin have on life history attributes of Indian meal moth and Angoumois grain moth. Stored grain is at risk to damage from Indian meal moth and Angoumois grain moth; therefore, Bt corn may provide a means of protecting this commodity from damage. Thus, the objective of this research was to quantify the effects of transgenic corn seed containing CrylAb delta-endotoxin on Indian meal moth and Angoumois grain moth survival, fecundity, and duration of development. Experiments with Bt grain, non-Bt isolines, and non-Bt grain were conducted in environmental chambers at 27 +/- 1 degrees C and > or = 60% RH in continuous dark. Fifty eggs were placed in ventilated pint jars containing 170 g of cracked or whole corn for the Indian meal moth and Angoumois grain moth, respectively. Emergence and fecundity were observed for 5 wk. Emergence and fecundity of Indian meal moth and emergence of Angoumois grain moth were significantly lower for individuals reared on P33V08 and N6800Bt, MON 810 and Bt-11 transformed hybrids, respectively, than on their non-Bt transformed isolines. Longer developmental times were observed for Indian meal moth reared on P33V08 and N6800Bt than their non-Bt-transformed isolines. These results indicate that MON 810 and Bt-11 CrylAb delta-endotoxin-containing kernels reduce laboratory populations of Indian meal moth and Angoumois grain moth. Thus, storing Bt-transformed grain is a management tactic that warrants bin scale testing and may effectively reduce Indian meal moth and Angoumois grain moth populations in grain without application of synthetic chemicals or pesticides.

Integration of Nonchemical, Postharvest Treatments for Control of Navel Orangeworm (Lepidoptera: Pyralidae) and Indianmeal Moth (Lepidoptera: Pyralidae) in Walnuts

We propose a treatment strategy combining an initial disinfestation treatment with I of 3 protective treatments as an alternative for chemical fumigation of walnuts for control of postharvest insect populations. The initial disinfestation treatment (0.4% O 2 for 6 d) was designed to disinfest walnuts of field populations of navel orangeworm. Amyelois transitella (Walker). The protective treatments were low temperature (10°C) storage, controlled atmosphere (5% O 2 ) storage, and application of the Indianmeal moth granulosis virus, and were designed to prevent establishment of Indianmeal moth, Plodia interpunctella (Hubner) The initial disinfestation treatment was effective against laboratory populations of navel orangeworm. Efficacy of protective treatments was determined by exposure to Indianmeal moth population levels far higher than those found in commercial walnut storage facilities. All 3 protective treatments prevented development of damaging Indianmeal moth populations as measured by pheromone trap catches and sample evaluation of the walnuts No Indianmeal months were trapped, nor were any seriously damaged walnuts (nuts with obvious damage that rendered the nutmeat less marketable or unmarketable) recovered from either low temperature or controlled atmosphere storage Very low numbers of moths (≤21/wk) ) were trapped from walnuts treated with virus, and only 0.2% of the walnuts re seriously damaged. In contrast, large numbers of moths (119-793/wk) were trapped from untreated nuts, and 35% of the sampled walnuts showed serious damage. Quality analysis by a commercial laboratory showed that overall walnut quality for all protective treatments was maintained at levels acceptable by industry standards.

Pirimiphos-Methyl Degradation and Insect Population Growth in Aerated and Unaerated Com Stored in Southeast Georgia: Small Bin Tests

Lots of 229 kg untreated seed corn and corn treated with 8 ppm pirimiphos-methyl were stored in unaerated bins and bins modified with a fan blower to provide aeration. The corn was infested artificially with adults of the red flour beetle, Tribolium castaneum (Herbst); the maize weevil, Sitophilus zeamais Motschulsky; and eggs of the Indianmeal moth, Plodia interpunctella (Hubner), to determine the effects of aeration on insect control in southeastern Georgia. Total temperature units in unaerated and aerated treated corn during the storage period of 15 October through 4 August were 5,729 and 5,196 degree-days, and moisture content was significantly greater in unaerated than in aerated bins. Pirimiphos-methyl degraded more quickly in unaerated than in aerated bins. No live insects were recovered from either unaerated or aerated treated bins. Total temperature units in untreated unaerated and untreated aerated corn were 5,745 and 5,391 degree-days. Percentage moisture content, percentage insect-damaged kernels, and number of beetles were greater in unaerated untreated than in aerated untreated bins. Indianmeal moth populations did not increase with time in untreated unaerated or untreated aerated bins. Aeration potentially can reduce insect pest population levels and subsequent damage in corn stored in southeastern Georgia.

Effects of Cleaning Peanuts on Insect Damage, Insect Population Growth and Insecticide Efficacy1

Abstract Farmers stock peanuts were either cleaned by removing foreign material and reducing loose-shell kernels (LSK) or left uncleaned before being treated with insecticides, stored, and artificially infested with several stored peanut insect pest species. The uncleaned peanuts contained only 2.8% foreign material. After 8 and 10 months the percentage of insect-damaged cracked pod kernels was 1.7 to 3.4 X greater in cleaned treated peanuts than in uncleaned treated peanuts, and there was a direct inverse relationship between the number of LSK and the percentage of damaged cracked pod kernels. After 8 and 10 months, the percentage of damaged cracked pod kernels in each class of peanuts, cleaned and uncleaned, was 1.6-5.7 X greater in peanuts treated with 52 ppm malathion than in peanuts treated with either 25 ppm chlorpyrifos-methyl or 25 ppm chlorpyrifos-methyl + 4 ppm methoprene. A significant difference in insect populations between cleaned and uncleaned peanuts occurred in untreated peanuts after two months, when almond moth and Indianmeal moth populations were greater in uncleaned peanuts. Thus, even a small amount of foreign material may provide a hospitable habitat for insect population growth. There were no significant differences in either insect damage or insect populations between chlorpyrifos-methyl and chlorpyrifos-methyl + methoprene.

Malathion Resistance in Indianmeal Moths (Lepidoptera: Pyralidae) Infesting Stored Corn and Wheat in the North-Central United States1

Forty-three strains of Pladia interpunctella (Hubner) were collected from grain bins on farms in nine midwestern states. Thirty-nine of the 43 strains were more than 17-fold resistant to malathion. None of 10 resistant strains tested were cross-resistant to chlorpyrifos methyl. Of six resistant strains assayed for malathion carboxylesterase activity, all had greatly elevated levels over those of a susceptible strain. The a-monoacid of malathion was the major hydrolysis product in all six resistant strains. When esterase electrophoretograms were prepared of 16 strains, ranging from purely susceptible to purely resistant, a good correlation was observed between resistance level and the staining intensity of certain esterase bands. We conclude that carboxylesterase-type malathion-specific resistance is epidemic in Indianmeal moth populations throughout the U.S. grain belt.

Susceptibility of Populations of Indianmeal Moth and Almond Moth to Bacillus thuringiensis123

Concentration-mortality studies with several populations of the Indianmeal moth, Plodia interpunctella (Hubner), and the almond moth, Ephestia cautella (Walker), were conducted with Bacillus thuringiensis subsp. kurstaki Berliner incorporated into a ground wheat diet. Indianmeal moth and almond moth populations differed as much as 6- and 10-fold, respectively, in responses to B. thuringiensis . The differences in both cases appeared to be related, in part, to population vigor. Midgut pH did not relate to population susceptibility in either species.