Ainsworth and Bisby's Dictionary of the Fungi

Understanding and Facilitating Adult Learning

The soil bacterium Bacillus thuringiensis (Bt) is the most successfully used biopesticide in agriculture, and its insecticidal protein genes are the primary transgenes used for insect control in transgenic crops. However, evolution of insect resistance to Bt toxins threatens the long-term future of Bt applications. To date, cases of resistance to Bt toxins have been reported in agricultural situations in six insect species, but the molecular basis for these cases of resistance remains unclear. Here we report that the resistance to the Bt toxin Cry1Ac in the cabbage looper, Trichoplusia ni, evolved in greenhouses, is associated with differential alteration of two midgut aminopeptidases N, APN1 and APN6, conferred by a trans-regulatory mechanism. Biochemical, proteomic, and molecular analyses showed that in the Cry1Ac-resistant T. ni, APN1 was significantly down-regulated, whereas APN6 was significantly up-regulated. The Cry1Ac resistance was correlated with down-regulation of APN1 but not with the up-regulation of APN6. The concurrent up-regulation of APN6 and down-regulation of APN1 might play a role in compensating for the loss of APN1 to minimize the fitness costs of the resistance. Along with identifying reduced expression of APN1 as the molecular basis of Bt resistance selected in an agricultural setting, our findings demonstrate the importance of APN1 to the mode of action of Bt toxin Cry1Ac.

https://www.pnas.org/content/pnas/108/34/14037.full.pdf

Differential alteration of two aminopeptidases N associated with resistance to Bacillus thuringiensis toxin Cry1Ac in cabbage looper

Biodegradable polymer based encapsulation of neem oil nanoemulsion for controlled release of Aza-A.

Little is known about genetic differentiation and gene flow in populations of insect species that have a high genetic variability in dispersal but lack morphologically visible morphs that disperse. These characteristics apply to the codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae), a major pest of fruits and nuts. Larvae were collected from three orchards each of pome fruits, stone fruits and nut trees in a major fruit growing area of Switzerland (Valais) and from six further (mainly apple) orchards throughout this country. Nine microsatellite loci were used to investigate genetic differentiation and the amount of gene flow among the sampled populations. All the loci were shown to be polymorphic in all populations. The number of alleles ranged from five to 15 over nine loci for the 15 populations. Significant genetic differentiation was noted among the populations from apple, apricot and walnut in the Valais region. Furthermore, among the eight populations sampled from apple in different geographic regions throughout Switzerland, AMOVA and pairwise FST analysis revealed significant population genetic differentiation even between populations collected from orchards 10 km apart. These results indicate that a distinct prevailing characteristic, in the present case the sedentary behaviour of the moth, can shape population architecture.

Microsatellites reveal genetic differentiation among populations in an insect species with high genetic variability in dispersal, the codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae).

The midge Contarinia nasturtii (Keiffer), a serious gall-forming insect pest of cruciferous plants in Europe and southwestern Asia, was first reported in the United States in summer 2004. It had not been recorded in North America until its discovery in Ontario, Canada, in 2000. Efficacy of 20 insecticides belonging to 12 different classes was evaluated by using a foliar spray, soil drench, or seed treatment method. The broccoli cultivar ‘Packman’ was used in all tests at the suitable stage of four to five true leaves. Results indicated that foliar sprays of λ-cyhalothrin, acephate, acetamiprid, chlorpyrifos, and methomyl reduced C. nasturtii larval populations by 96.7–100%. Except for acetamiprid, the other four insecticides also were effective against adults and provided 100% mortality after 24 h. When applied by drench, acetamiprid, imidacloprid, and thiamethoxam provided 100% control of C. nasturtii larvae, and the duration of efficacy lasted at least 7 wk. When applied as seed treatment, clot...

Evaluation of Insecticides and Application Methods Against Contarinia nasturtii (Diptera: Cecidomyiidae), a New Invasive Insect Pest in the United States

The midge Contarinia nasturtii Kieffer (Diptera: Cecidomyiidae) was first confirmed in North America in Ontario, Canada, in 2000. The insect is now distributed throughout many counties in the provinces of Ontario and Quebec. Nearly 1,200 farms in the northeastern United States that grow cruciferous vegetables are at risk for C. nasturtii infestation if this insect were to spread to that region. Over a period of 3 yr (2002-2004), approximately 3,000 ha of crops on 94 farms in western New York State was scouted for C. nasturtii, but none were found. In 2004, 42 experimental pheromone traps were placed in fields of cruciferous vegetables in eight counties. C. nasturtii males were captured at low levels (1-50 per trap / 8 wk) on four farms in Niagara County, but not at any other site. C. nasturtii larvae were found in plant tissue at one of the four farms. Insect specimens were identified by morphological methods, molecular methods, or both. This is the first confirmation of C. nasturtii in the United States, which we believe was made possible by the combined use of pheromone traps, morphological characters of trapped adults, and molecular methods. The early detection in New York presents an opportunity to implement measures to limit the spread and establishment of C. nasturtii across the state and into other regions of the United States.

http://web.entomology.cornell.edu/shelton/publications/pdf/Kikkert%20et%20al%202006%20Detection%20of%20swede%20midge%20in%20NY,%20a%20new%20pest%20of%20cruciferous%20plants%20in%20the%20US.pdf

Detection of Contarinia nasturtii (Diptera: Cecidomyiidae) in New York, a New Pest of Cruciferous Plants in the United States

The diamondback moth, Plutella xylostella (L.), is considered the most universally distributed of all Lepidoptera and the main insect pest of crucifers worldwide. Although P. xylostella is confined to feeding on plants within the Cruciferae, this diverse family contains a wide host of weed species and cultivated plants that occur throughout the world. Over the last several decades the importance of crucifers in the human diet has increased, resulting in increased crucifer production and changing management practices. Where once crucifers were part of smaller diversified cropping systems, they are often now grown as monocultures under intensive cultivation practices, including year-round production. In areas of China, south-east Asia and other areas where crucifers are important to the human diet, there may be more than 20 generations of P. xylostella annually. As production practices have changed and the demand for damage-free produce has intensified, farmers have relied on intensive use of insecticides which, in turn, has contributed to insecticide resistance, reduced effectiveness of natural enemies, frequent control failures, and some environmental and human health concerns. Because of the health benefits and cultural significance of crucifers, especially in Asian populations, production will continue to increase. What have we learned from the past that will allow us to provide better management of P. xylostella in the future? A central element will be to develop preventative tactics and ‘rescue’ treatments which conserve natural enemies, promote resistance management strategies, and utilize cultural control practices that rely on understanding the agroecology of P. xylostella. Most importantly, successful management of P. xylostella will rely on farmers and scientists taking a more ‘regional perspective’ that includes information on P. xylostella movement and the effects of management tactics on their behaviour and population genetics on a community level.

The management of diamondback moth and other crucifer pests : proceedings of the fifth international workshop

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Evaluation of Insecticides and Application Methods Against Contarinia nasturtii (Diptera: Cecidomyiidae), a New Invasive Insect Pest in the United States

Detection of Contarinia nasturtii (Diptera: Cecidomyiidae) in New York, a New Pest of Cruciferous Plants in the United States

The management of diamondback moth and other crucifer pests : proceedings of the fifth international workshop