Incidence of Bactericera cockerelli (Hemiptera: Triozidae) Under Different Pesticide Regimes in the Lower Columbia Basin.

Zebra chip is a potato disease transmitted by the potato psyllid Bactericera cockerelli (Sulc) and distributed across several regions of the United States. Because of its potentially devastating effects, the disease represents a threat to the potato production and the industry particularly in the Pacific Northwest, where it was first detected in 2011. Efforts to control the disease primarily focus on managing the vector using pesticides. In this study, the effectiveness of two pesticide spray programs in 2012 ("FULL" and "REDUCED") and three in 2013 ("FULL 1," "FULL 2," and "REDUCED") against the potato psyllid was evaluated. Yellow sticky cards were used to monitor the adults, whereas immatures were evaluated by sampling the leaves. Overall, the vector infestation level in both years was low. The mean total number of adults per trap in 2012 was 1.5, 5, and 12 for "FULL," "REDUCED," and the control, respectively, while in 2013 was 10.3, 20.7, 17.7, and 52 for "FULL 1," "FULL 2," "REDUCED," and the control, respectively. For each particular year, season-long regimes were most effective at controlling the pest than targeted applications; however, there was no statistical difference among regimes ("FULL" or "REDUCED") after early July, when the first psyllids were detected, until mid-August. Moreover, this number was similar to the control. Also, psyllid density was uniform across sticky traps, and no clear relationship was found between the proportion of Lso-infective psyllids and zebra chip disease intensity.

Effects of reduced-risk pesticides and plant growth regulators on rove beetle (Coleoptera: Staphylinidae) adults.

In many regions, pest management of greenhouse crops relies on the use of biological control agents; however, pesticides are also widely used, especially when dealing with multiple arthropod pests and attempting to maintain high esthetic standards. As such, there is interest in using biological control agents in conjunction with chemical control. However, the prospects of combining natural enemies and pesticides are not well known in many systems. The rove beetle, Atheta coriaria (Kraatz), is a biological control agent mainly used against fungus gnats (Bradysia spp.). This study evaluated the effects of reduced-risk pesticides and plant growth regulators on A. coriaria adult survival, development, and prey consumption under laboratory conditions. Rove beetle survival was consistently higher when adults were released 24 h after rather than before applying pesticides. The pesticides acetamiprid, lambda-cyhalothrin, and cyfluthrin were harmful to rove beetle adults, whereas Beauveria bassiana (Balsamo) Vuillemin, azadirachtin, and organic oils (cinnamon oils, rosemary oil, thyme oil, and clove oil) were nontoxic to A. coriaria adults. Similarly, the plant growth regulators acymidol, paclobutrazol, and uniconazole were not harmful to rove beetle adults. In addition, B. bassiana, azadirachtin, kinoprene, organic oils, and the plant growth regulators did not negatively affect A. coriaria development. However, B. bassiana did negatively affect adult prey consumption. This study demonstrated that A. coriaria may not be used when applying the pesticides, acetamiprid, lambda-cyhalothrin, and cyfluthrin, whereas organic oils, B. bassiana, azadirachtin, and the plant growth regulators evaluated may be used in conjunction with A. coriaria adults. As such, these compounds may be used in combination with A. coriaria in greenhouse production systems.

Virulence analysis of Hessian fly populations from Texas, Oklahoma, and Kansas.

In recent years, the number of wheat, Triticum aestivum L., fields heavily infested by Hessian fly, Mayetiola destructor (Say), has increased in the Great Plains of the United States. Historically, resistance genes in wheat have been the most efficient means of controlling this insect pest. To determine which resistance genes are still effective in this area, virulence of six Hessian fly populations from Texas, Oklahoma, and Kansas was determined, using the resistance genes H3, H4, H5, H6, H7H8, H9, H10, H11, H12, H13, H16, H17, H18, H21, H22, H23, H24, H25, H26, H31, and Hdic. Five of the tested genes, H13, H21, H25, H26, and Hdic, conferred high levels of resistance (> 80% of plants scored resistant) to all tested populations. Resistance levels for other genes varied depending on which Hessian fly population they were tested against. Biotype composition analysis of insects collected directly from wheat fields in Grayson County, TX, revealed that the proportion of individuals within this population virulent to the major resistance genes was highly variable (89% for H6, 58% for H9, 28% for H5, 22% for H26, 15% for H3, 9% for H18, 4% for H21, and 0% for H13). Results also revealed that the percentages of biotypes virulent to specific resistance genes in a given population are highly correlated (r2 = 0.97) with the percentages of susceptible plants in a virulence test. This suggests that virulence assays, which require less time and effort, can be used to approximate biotype composition.