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Beet western yellows virus (BWYV; genus Polerovirus, family Luteoviridae) is one of the most important viruses causing yellowing disease of many field and vegetable crops. This study isolated different poleroviruses from sugar beet, spinach, radish and brassica in Japan, and identified them as BWYV‐JP, Beet leaf yellowing virus (BLYV), Brassica yellows virus (BrYV) and BrYV‐R (radish strain) based on host range and molecular analysis. Among over 100 plant species from 19 families inoculated with the vector Myzus persicae, about half of the species in 13 families were infected with some of these viruses. BLYV shared a similar host range to Beet mild yellowing virus (BMYV). These had a much more limited host range than BWYV‐JP, which resembled BWYV‐USA. The host range of BrYV was similar to that of Turnip yellows virus (TuYV). Phylogenetic analyses at the 5′ portion (replication‐related gene) of the genome showed that BLYV, BMYV, BWYV (‐JP and ‐USA) and Cucurbit aphid‐borne yellows virus (CABYV) formed one large group, whereas BrYV and TuYV were grouped together. BLYV and BWYV were most closely related to each other, and were more closely related to CABYV than to BMYV. However, at the 3′ end (coat protein gene), BLYV and BWYV‐JP formed a distinct group, separated from the BrYV group, which in turn was more closely related to BWYV‐USA, BMYV, TuYV and Beet chlorosis virus, a group originating from outside Asia. Thus, this study presents host range differences and phylogeographical relationships of BWYV‐like poleroviruses that are distributed worldwide. [ABSTRACT FROM AUTHOR]

Abstract: Organophosphate and carbamate insecticides exert their neurotoxic effects by inhibiting acetylcholinesterase (AChE), thereby, prolonging the action of acetylcholine at cholinergic synapses, resulting in neuronal hyperexcitation. Mutations at the AChE target site confer modified acetylcholinesterase (MACE) phenotypes. Target-site insensitivity of AChE was characterized in field-collected, tobacco-adapted forms of the green peach aphid, Myzus persicae (Sulzer), from nine different states in the eastern United States from 2004 to 2007. The specific activity of the AChE among the 65 aphid colonies screened by Ellman''s assay ranged from 0.017–0.259U/min/mg protein. Eight colonies, with a wide range of specific activities were chosen to study the inhibition of AChE in the presence of two carbamate insecticides, methomyl and pirimicarb. IC50 values for methomyl ranged from 0.35 to 2.4μM, while six out of eight colonies had lower values that ranged from 0.16 to 0.30μM for pirimicarb. Two colonies that were inhibited by methomyl had very high IC50 values for pirimicarb, 40.4 and 98.6μM respectively. The target-site insensitivity in these two colonies that are resistant to pirimicarb could be due to an ace2 gene mutation. This is the first instance where MACE phenotypes in M. persicae from the United States were studied and confirmed. The results indicate that the possible insensitivity due to MACE resistance in some colonies may render selected carbamate insecticides ineffective. Concerns of MACE resistance in managing the tobacco-adapted form of the green peach aphid on tobacco in the United States are discussed. [Copyright &y& Elsevier]

Application of imidacloprid to the soil in which Tabasco pepper, Capsicum frutescens L., seedlings were growing was highly effective against the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae). In just 48 h after the soil drench, aphid numbers on treated plants declined from 292.1 to 33.0 per plant, a reduction of 89%. By 72 and 96 h after the application, the reductions were 97 and 100%, respectively. Reductions in green peach aphid numbers also indicated that imidacloprid readily moved throughout the Tabasco pepper plant. Although, initial green peach aphid reductions at 24 and 48 h after imidacloprid application to soil, were greater on the lower leaves than on the upper leaves, by 72 h toxicity was high throughout the plant. At 48 h, overall green peach aphid reduction on seedlings grown in wet soil was significantly higher than that on plants growing in the drier soil. Regardless of soil moisture or leaf location, no live green peach aphids were detected on treated seedlings after 96 h. After the initial uptake period, toxicity to green peach aphid remained high for 5 wk. Under Tabasco pepper production conditions in Central America, the greatest need for aphid management is just after transplanting. Imidacloprid soil drenches before transplanting should offer the Tabasco pepper producer an extended period of aphid-free production. [ABSTRACT FROM AUTHOR]

Potato leafroll virus (PLRV) causes one of the most serious aphid-transmitted diseases affecting yield and quality of potatoes, Solanum tuberosum (L.), grown in the United States. The green peach aphid, Myzus persicae (Sulzer), is considered to be by far the most efficient vector of this virus. Even the most strict aphid control strategy may not prevent the spread of PLRV unless measures also are taken to keep virus source plants within and outside the crop at a minimum. Hairy nightshade, Solarium sarrachoides (Sendtner), is one of the preferred weed hosts for green peach aphid. The potential of this weed as an aphid reservoir and virus source and its spread or perpetuation were investigated. With the use of double antibody sandwich enzyme-linked immunosorbent assay, it was confirmed that green peach aphid can transmit PLRV to hairy nightshade and that aphids can become viruliferous after feeding on infected hairy nightshade plants. Transmission from hairy nightshade to potato is 4 times the rate of potato to potato or potato to hairy nightshade. The green peach aphid preferred hairy nightshade over potato plants and reproduced at a higher rate on hairy nightshade than on potato. Therefore, a low level of PLRV-hairy nightshade infection could enhance the disease spread in the field. [ABSTRACT FROM AUTHOR]