Roger D. Moon

Areawide Suppression of European Corn Borer with Bt Maize Reaps Savings to Non-Bt Maize Growers

Economic Benefits of Bt Maize Maize containing a transgenically expressed toxin originating from Bacillus thuringiensis (Bt maize) is planted across the United States to combat insect herbivory. Non-Bt Maize is also planted alongside Bt maize fields to provide refuges for the insects, which helps to prevent resistance to Bt maize from evolving. Hutchison et al. (p. 222; see the Perspective by Tabashnik) analyzed how Bt maize affected the economic impact of the European corn borer moth in the midwestern United States, as well as its population dynamics. Larval density, a predictor of corn borer population size, has dropped in correlation with the percentage of Bt maize planted. In the highest Bt maize producing state, the positive effects of Bt maize in controlling insect herbivore populations extended to non-Bt maize. Furthermore, the decrease in insect populations demonstrated an overall economic benefit outweighing the overall extra costs associated with planting Bt maize. Genetically modified maize generally reduces insect populations to relieve pest pressure on unmodified neighboring crops. Transgenic maize engineered to express insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) has become widely adopted in U.S. agriculture. In 2009, Bt maize was planted on more than 22.2 million hectares, constituting 63% of the U.S. crop. Using statistical analysis of per capita growth rate estimates, we found that areawide suppression of the primary pest Ostrinia nubilalis (European corn borer) is associated with Bt maize use. Cumulative benefits over 14 years are an estimated

Economic Impact of Stable Flies (Diptera: Muscidae) on Dairy and Beef Cattle Production

3.2 billion for maize growers in Illinois, Minnesota, and Wisconsin, with more than

Practical sampling plans for varroa destructor (Acari: Varroidae) in apis mellifera (Hymenoptera: Apidae) colonies and apiaries

2.4 billion of this total accruing to non-Bt maize growers. Comparable estimates for Iowa and Nebraska are

Intensive rotational grazing for dairy cattle feeding

3.6 billion in total, with

Insecticide resistance in house flies from the United States: Resistance levels and frequency of pyrethroid resistance alleles

1.9 billion for non-Bt maize growers. These results affirm theoretical predictions of pest population suppression and highlight economic incentives for growers to maintain non-Bt maize refugia for sustainable insect resistance management.

Seasonal dynamics and variation among sheep in densities of the sheep biting louse, Bovicola ovis

ABSTRACT Stable flies, Stomoxys calcitrans (L.), are among the most damaging arthropod pests of cattle worldwide. The last estimate of their economic impact on United States cattle production was published 20 yr ago and placed losses at

Density of itch mite, Sarcoptes scabiei (Acari: Sarcoptidae) and temporal development of cutaneous hypersensitivity in swine mange.

608 million. Subsequently, several studies of effects of stable flies on beef cattle weight gain and feed efficiency have been published, and stable flies have become increasingly recognized as pests of cattle on pasture and range. We analyzed published studies and developed yield-loss functions to relate stable fly infestation levels to cattle productivity, and then estimated the economic impact of stable flies on cattle production in the United States. Four industry sectors were considered: dairy, cow-calf, pastured stockers, and feeder cattle. In studies reporting stable fly infestation levels of individual herds, median annual per animal production losses were estimated to be 139 kg of milk for dairy cows, and 6, 26, and 9 kg body weight for preweanling calves, pastured stockers, and feeder cattle, respectively. The 200,000 stable flies emerging from an average sized winter hay feeding site reduce annual milk production of 50 dairy cows by an estimated 890 kg and weight gain of 50 preweanling calves, stockers, or feeder cattle by 58, 680, or 84 kg. In 2009 dollars, the value of these losses would be

Growth and Survival of Monarch Butterflies (Lepidoptera: Danaidae) After Exposure to Permethrin Barrier Treatments

254,

Pruritis and dermal response to insect antigens in sheep infested with Bovicola ovis

132,

Dispersal of stable flies (Diptera: Muscidae) from larval development sites in a Nebraska landscape.

1,279, or