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Transgenic corn and cotton that produce Cry and Vip3Aa toxins derived from Bacillus thuringiensis (Bt) are widely planted in the United States to control lepidopteran pests. The sustainability of these Bt crops is threatened because the corn earworm/bollworm, Helicoverpa zea (Boddie), is evolving a resistance to these toxins. Using Bt sweet corn as a sentinel plant to monitor the evolution of resistance, collaborators established 146 trials in twenty-five states and five Canadian provinces during 2020–2022. The study evaluated overall changes in the phenotypic frequency of resistance (the ratio of larval densities in Bt ears relative to densities in non-Bt ears) in H. zea populations and the range of resistance allele frequencies for Cry1Ab and Vip3Aa. The results revealed a widespread resistance to Cry1Ab, Cry2Ab2, and Cry1A.105 Cry toxins, with higher numbers of larvae surviving in Bt ears than in non-Bt ears at many trial locations. Depending on assumptions about the inheritance of resistance, allele frequencies for Cry1Ab ranged from 0.465 (dominant resistance) to 0.995 (recessive resistance). Although Vip3Aa provided high control efficacy against H. zea, the results show a notable increase in ear damage and a number of surviving older larvae, particularly at southern locations. Assuming recessive resistance, the estimated resistance allele frequencies for Vip3Aa ranged from 0.115 in the Gulf states to 0.032 at more northern locations. These findings indicate that better resistance management practices are urgently needed to sustain efficacy the of corn and cotton that produce Vip3Aa.

The dataset contains irrigation water quality parameters including iron concentrations (ferrous, ferric, and total) and turbidity measurements from a blueberry farm in southern New Jersey. Data was collected from May through June for 14 weeks in 2015 using a SMART3 Colorimeter™. Water samples were taken from the pump at the irrigation well and compared to samples taken from driplines at individual fields. All samples were analyzed in the field following the equipment׳s manual, except for ferric iron, which was calculated from the ferrous iron and total iron concentrations. Statistical analyses were performed on the dataset to understand the data. This data is being made available to increase the understanding of clogging in drip irrigation systems and to assist in the management of drip irrigation systems.

This study was designed to determine the efficacy of binary pesticide mixtures against one of the most important insect pests of greenhouse-grown horticultural crops, western flower thrips (Frankliniella occidentalis). Two separate experiments were conducted under greenhouse conditions to simulate a greenhouse production cycle using yellow transvaal daisy (Gerbera jamesonii) cut flowers, which were artificially infested with a known number of western flower thrips. The pesticides used in the two experiments were spinosad, pymetrozine, abamectin, pyridalyl, fluvalinate, chlorfenapyr, bifenazate, azadirachtin, petroleum oil, tolfenpyrad, fenhexamid, azoxystrobin, and spirotetramat. Pesticide mixtures were evaluated at the recommended labeled rates (Expt. 1) and assessments were made to determine if adding didecyl dimethyl ammonium chloride enhanced the efficacy of the pesticide mixtures (Expt. 2). Results from Expt. 1 indicated that many of the binary pesticide mixtures provided ≥80% mortality of western flower thrips although this was a baseline population without previous exposure to pesticides. In Expt. 2, the addition of didecyl dimethyl ammonium chloride failed to increase the efficacy of most of the designated pesticide mixtures compared with the pesticides applied separately. Furthermore, none of the binary pesticide mixtures were phytotoxic to the transvaal daisy flowers. Although there are issues associated with using pesticide mixtures such as the potential for resistance developing to different pesticides in mixtures, greenhouse producers combine pesticides together to reduce labor costs and expand the spectrum of activity against insect and mite (Tetranychidae) pests. Therefore, the relevance of this information is that greenhouse producers now understand which pesticide mixtures may be used and those that should be avoided when suppressing populations of western flower thrips thus minimizing feeding damage to greenhouse-grown horticultural crops.

This study was conducted to assess the direct and indirect effects of Growstones aggregates, which are made from recycled glass, on fungus gnat, Bradysia sp. nr. coprophila (Diptera: Sciaridae), adult emergence, female egg-laying capacity, and egg survival. A series of experiments were performed under laboratory conditions to evaluate the effect of different sizes (2.0 to 10.0 mm) of Growstones aggregates, layer thicknesses (0.63 to 3.18 cm), and the use of the biological control agent, the rove beetle, Dalotia coriaria, along with different thicknesses (1.27 and 3.18 cm) of small Growstones aggregates on fungus gnat adult emergence. For each experiment, Growstones aggregates were applied to the surface of the growing medium in 473-mL polypropylene deli containers. This study demonstrated that the thickest (3.18 cm) layer of small (2.0 mm) Growstones aggregates significantly reduced or delayed the emergence of fungus gnat adults. In addition, the thickest layer of small Growstones aggregates may have indirectly affected egg survival. However, the use of Growstones along with rove beetle adults did not significantly reduce fungus gnat adult emergence. Fungus gnats are a commonly encountered insect pest of greenhouses (Dennis, 1978; Hamlen and Mead, 1979) and are typically a problem in moist environments such as those that occur in propagation or plug production (Cloyd, 2000). Adults cause minimal direct damage to plants; however, a single female Bradysia sp. nr. coprophila Lintner (Diptera: Sciaridae) can lay 96 eggs on the surface of the growing medium (Meers and Cloyd, 2005). After eggs hatch, larvae feed on plant roots causing plant stunting, wilting, and possibly plant death (Jarvis et al., 1993; Springer, 1995; Wilkinson and Daugherty, 1970). In addition, indirect damage by larvae is associated with transmission of certain soilborne plant pathogens (Gardiner et al., 1990; Gillespie and Menzies, 1993; Jarvis et al., 1993). Currently, insecticides applied as drenches to the growing medium are an effective management strategy against fungus gnat larvae (Hamlen and Mead, 1979; Lindquist, 1994; Lindquist et al., 1985). However, as a result of the limited number of insecticides registered for use in greenhouses, and the costs associated with development and registration of new insecticides (Lewis, 1977), it is important to judiciously use the currently available compounds (Lindquist et al., 1985). Biological control agents such as the rove beetle, Dalotia coriaria Kraatz (Coleoptera: Staphylinidae), have been shown to be an effective predator against fungus gnat larvae (Carney et al., 2002; Echegaray, 2012). However, a number of insecticides are directly and indirectly harmful to rove beetles (Cloyd et al., 2009). Consequently, physical barriers may be a long-term management strategy that could also be used with biological control agents (Banks, 1976). Physical barriers are used to alter the environment so as to make it inaccessible to insect pests (Banks, 1976). There are a number of benefits associated with physical barriers such as compatibility with other insect pest management strategies including biological control and minimal impact on the environment (Boiteau, 2002). Nonetheless, physical barriers do not reduce an insect population immediately, which typically happens with most insecticides (Boiteau, 2002). A physical barrier could be placed on the surface of the growing medium to inhibit adult fungus gnat emergence or possibly reduce adult female egg-laying or egg survival (Cloyd et al., 2007a), whereas rove beetles feed on fungus gnat larvae in the growing medium. Physical barriers have been evaluated as a pest management strategy against insect pests, specifically the fungus gnat, Bradysia sp. nr. coprophila (Cloyd et al., 2007a). Previous research by Cloyd et al. (2007a) evaluated the effect of dry and moist diatomaceous earth and sand as a physical barrier against fungus gnats. Diatomaceous earth affects insects either by removing or absorbing oils and waxes on the outer insect cuticle or by abrading the cuticle causing extensive moisture loss leading to desiccation. However, when diatomaceous earth becomes moist, it loses any abrasive properties (Korunic, 1998). Cloyd et al. (2007a) determined that both dry and moist diatomaceous earth and sand formed cracks or air pockets over time, which decreased their ability to negatively affect fungus gnats. This suggests that diatomaceous earth and sand may not be effective physical barriers. Despite this, there are other materials that may act as physical barriers against fungus gnats such as Growstones (Growstone, Inc., Albuquerque, NM). Growstones aggregates are processed from 100% recycled glass and are primarily used as a hydroponic growing substrate in which plants are inserted into containers containing Growstones aggregates. A nutrient solution is applied to the container. Growstones aggregates are lightweight and can be manufactured into different particle sizes (Evans, 2011). It is possible that Growstones aggregates may serve as a physical barrier against fungus gnats in greenhouses. Therefore, the objectives of this study were 3-fold: 1) to determine the direct effect of Growstones aggregates applied to the growing medium surface on fungus gnat adult emergence; 2) to assess the indirect effect of Growstones aggregates placed on the growing medium surface on female egglaying and/or egg survival and subsequent adult emergence; and 3) to determine if using rove beetle, Dalotia coriaria, adults in conjunction with Growstones is synergistic in affecting fungus gnat adult emergence. Materials and Methods Fungus gnat colony. Laboratory-reared colonies of the fungus gnat, Bradysia sp. nr. coprophila, were located in the Department of Entomology at Kansas State University (Manhattan, KS) and maintained in 8.0-L plastic containers with tight-sealing lids. Openings ( 15 cm square) were cut in the lids and then insect screening [50 · 24 (0.2 · 0.8 mm; Greentek, Edgerton, WI)] was hotglued to the lids to allow for ventilation. The Received for publication 27 Mar. 2014. Accepted for publication 28 Apr. 2014. We thank Growstones, Inc. (Albuquerque, New Mexico) for providing the funds necessary to conduct this research. In addition, we thank Paula Costa of Growstones, Inc. (Albuquerque, NM) and Dr. Mary Beth Kirkham in the Department of Agronomy at Kansas State University (Manhattan, KS) for their valuable feedback associated with previous drafts of the manuscript. To whom reprint requests should be addressed; e-mail rcloyd@ksu.edu. HORTSCIENCE VOL. 49(7) JULY 2014 905 DISEASE AND PEST MANAGEMENT

Temperature‐based degree‐day models describe insect seasonality and to predict key phenological events. We expand on the use of a temperature‐based process defining timing of reproduction through the incorporation of female reproductive physiology for the invasive pentatomid species Halyomorpha halys, the brown marmorated stink bug. A five‐stage ranking system based on ovary development was able to distinguish between the reproductive statuses of field‐collected females. Application of this ranking method described aspects of H. halys’ seasonality, overwintering biology, and phenology across geographic locations. Female H. halys were collected in the US from NJ, WV, NC, OR, and two sites in PA in 2006–2008 (Allentown, PA only) and 2012–2014. Results identify that H. halys enters reproductive diapause in temperate locations in the fall and that a delay occurs in developmental maturity after diapause termination in the spring. Modification of the Snyder method to identify biofix determined 12.7‐hr photoperiod as the best fit to define initiation of reproduction in the spring. Applying the biofix, we demonstrated significant differences between locations for the rate at which the overwintering generation transition into reproductive status and the factors contributing to this difference require further study. For example, after including abiotic variables influencing development such as temperature and photoperiod (critical diapause cue), reproduction occurred earlier in OR and for an extended period in NJ. This data describe a method to investigate insect seasonality by incorporating physiological development across multiple regions that can clarify phenology for insects with overlapping generations.