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The revocation of chlorpyrifos tolerances in 2022 left sweetpotato growers without their most important tool to combat a complex of soil-borne root pests that includes wireworms (Coleoptera: Elateridae). Since then, growers have reported increased root damage despite a rapid pivot to pyrethroid-based management systems to replace mechanically incorporated preplant chlorpyrifos broadcast sprays. Our goal was to evaluate the efficacy of alternative insecticide chemistries and application methods to expand the portfolio of management options for wireworms, specifically Conoderus spp. and Melanotus communis (Gyllenhal). We tested (i) insecticidal transplant water drenches and (ii) a foliar spray program targeting adult elaterids. We found that incorporating insecticides into transplant water reduced wireworm damage when compared to untreated transplant water. Our treatments included a recently registered meta-diamide, broflanilide, which represents a promising path to diversify active ingredients and shift away from an overreliance on preplant and post-directed pyrethroid soil sprays. Foliar spray plots had less damage than plots that did not receive foliar sprays. One benefit of adult-focused management is the availability of effective monitoring tools such as sex pheromones and blacklight trapping. Developing a robust adult monitoring program would enable more precise applications of foliar insecticides versus season-long prophylactic soil sprays targeting larvae. Our results demonstrated a significant benefit to both alternative delivery methods.These management alternatives could expand treatment options beyond traditional preplant and post-directed pyrethroid sprays.

Radiographic imaging was used to study corn wireworm, Melanotus communis (Gyllenhal) (Coleoptera: Elateridae), behavior in the soil relative to Irish potato, Solanum tuberosum L. (Solanales: Solanaceae), placed above a barrier of insecticide-treated soil. Behavioral response to three insecticides was evaluated by 1) calculating the percentage of wireworms that breached the zone of insecticide-treated soil, 2) comparing the variability in the mean distance between each wireworm and the center of the tuber in each arena compartment, 3) comparing the cumulative distance of wireworm travel, and 4) comparing incidence and severity of wireworm-inflicted tuber injury. The percentage of wireworms that breached the insecticide zone was significantly lower in the bifenthrin treatment than the untreated check, but not different from clothianidin or fipronil. Limited difference between treatments in relation to the cumulative distance traveled was observed where bifenthrin inhibited travel distance more than other insecticides tested. No difference in variability of movement in relation to the food source was observed between treatments. Bifenthrin and fipronil treatments resulted in the greatest reduction in wireworm injury incidence and severity compared to the untreated check. While bifenthrin suppressed wireworm movement and feeding more than other insecticides tested, exposure to fipronil resulted in higher wireworm mortality at all sample dates.

The corn wireworm, Melanotus communis (Gyllenhal) (Coleoptera: Elateridae), is an important soil insect pest of Florida sugar cane (Saccharum spp.; Poaceae). The objective of this study was to determine the host plant preference of M. communis adults and larvae to weeds and sugar cane varieties found in Florida sugar cane fields. Three sugar cane varieties, 3 grass weeds, and 3 broadleaf weeds were tested for their attraction to the insects in free choice tests. After a 24 h exposure to whole plant extracts (juices), most adults were found in sugar cane varieties, followed by grass weeds, then broadleaf weeds. After a 48 h exposure to chopped roots in muck soil, most larvae were found in sugar cane varieties, followed by grass weeds, then broadleaf weeds. After a 48 h exposure to chopped roots in sandy soil, most larvae were found in sugar cane varieties, followed by broadleaf weeds, then grass weeds. Our data show that in free choice tests, both M. communis adults and larvae prefer sugar cane over weeds present in Florida sugar cane fields.

The neem tree Azadirachta indica A. Juss produces numerous allelochemical compounds. The most effective active ingredient in A. indica based insecticides is azadirachtin. We found that azadirachtin did not cause mortality, antifeeding responses, or change growth rate of Melanotus communis (Gyllenhal) wireworms. However, azadirachtin treated soil was repellent to the wireworms. This is the first report of azadirachtin being repellent to any of the large and economically important family of Elateridae.

Wireworms (larval Elateridae) reduce the stand of newly planted sugarcane (complex hybrid of Saccharum spp.) directly by damaging growing points and indirectly by facilitating disease introduction. No research has evaluated resistance or tolerance of sugarcane genotypes grown in Florida to wireworm. Eleven genotypes of sugarcane and a S.   spontaneum genotype were subjected to corn wireworm, Melanotus communis (Gyllenhall) (Coleoptera: Elateridae), in greenhouse experiments to evaluate potential host plant resistance. The experiments were designed to measure the effects of wireworms on the first 90 days of growth. Sugarcane stalk sections were planted in trays of soil with and without wireworms in 2010 and 2011. Stand count, dry weight, and percentage of nodes damaged were evaluated. Wireworms reduced stand and dry weight by 40–60 %. Several genotypes were able to produce acceptable stands in wireworm-infested trays by emerging quickly and producing many tillers. CP 88-1762, CP 89-2143, and CP 03-1912 did not suffer statistically significant losses of stand or biomass due to wireworms in either year. Our findings suggest that genotype resistance should be considered as an important component of an integrated program aimed at reducing the use of insecticides to control wireworms in sugarcane.

Wireworms (larval Elateridae) are perennial pests of newly planted sugarcane causing stand loss directly by damaging growing points and indirectly by introducing disease. Two organophosphate insecticides, phorate and ethoprop, are currently labeled for controlling wireworms in sugar cane. In the first experiment, 4 rates of phorate (100, 87.5, 75, and 62.5% of the current maximum field rate) were used in 2 different types of soil: Dania Muck and Immokalee Fine Sand. In the second experiment, 4 rates of phorate and ethoprop (100, 75, 50, and 25% of current maximum field rates) were used in a Lauderhill Muck soil. A no-treatment and a wireworm-free treatment were used as controls in both experiments. The effect of the insecticide was evaluated in simulated field experiments conducted in 18.9-L (5-gallon) buckets filled with soil and artificially infested with 10 wireworms (Melanotus communis (Gyllenhall), Coleoptera: Elateridae) per bucket. After 60 d, the contents of the buckets were emptied to evaluate damage to the plant and count the surviving wireworms. Insecticides resulted in fewer live wireworms and reduced damage to sugarcane shoots, roots, and seed pieces compared to the no-treatment control. In the first experiment, phorate proved to be very effective at controlling wireworms even at the 62.5% rate. Phorate was more effective in the Immokalee Fine Sand than in the Dania Muck. In the second experiment, phorate was found to be more effective at reducing stand loss and wireworm numbers than ethoprop. Translation by the authors.

Larvae of Melanotus communis (Gyllenhal) collected from sugarcane fields in southern Florida were held in soil flooded with water for 1, 2, 3, 4, 5 or 6 weeks at 18, 21, 24 or 27°C. At each temperature, regression analyses indicated that the percentage of wireworms killed increased linearly as flood duration was increased. Increasing the temperature maintained during a flood significantly increased the percentage of wireworms that died. Multiple regression analysis indicated that Y=-94.4+7.1X1+4.3X2, where Y was the expected percent mortality, X1was flood duration in weeks, and X2was temperature in degrees Celsius (R2=.76). The equation may be used to estimate how long a flood should be continued at a given temperature to obtain a desired level of wireworm control under field conditions. /// Se colectaron larvas de Melanotus communis (Gyllenhal) en campos de cana de azucar en el sur de Florida y se mantuvieron en suelo inundado con agua por espacio de 1, 2, 3, 4, 5 o 6 semanas a temperaturas de 18, 21, 24, or o 27 oC. Los analisis de regresion indicaron que para cada temperatura, el percentaje de mortalidad de los gusanos alambre incrementaba linearmente a medida que el periodo de inundacion aumentaba. El incremento de temperatura durante una inundacion, aumento el porcentaje de mortalidad de los gusanos alambre. Los analisis de regresiones multiples indicaron que Y = -94.4 + 7.1X1 + 4.3X2, donde Y es el porcentaje de mortalidad esperada, X1 es la duracion de la inundacion en semanas, y X2 fue la temperatura en grados Celsius (R2=.76). La ecuacion puede ser usada para estimar por cuanto tiempo debe continuarse una inundacion a una temperatura dada con el fin de obtener un nivel deseado de control de los gusanos alambre bajo condiciones de campo.

Experiments were conducted during two consecutive growing seasons to evaluate food baits for pre-plant sampling of wireworms that attack potato in southern Florida. Wireworm species studied were: Melanotus communis (Gyllenhal), southern potato wireworm, Conoderus falli Lane, C. amplicollis (Gyllenhal), and C. rudis (Brown). Baits evaluated were hybrid sweet corn seed, hybrid sorghum-sudangrass seed, a 1:1 mixture of corn and sorghum-sudangrass seed, a whole sweet corn ear, potato seed pieces, a 1:1 mixture of oatmeal and corn flake, rolled oats, and carrots. In the first year, numbers of wireworm larvae did not differ between food bait and soil samples for most food baits tested. Melanotus communis larvae were most numerous in the oatmeal-corn flake and sorghum-sudangrass seed baits. Conoderus spp. larvae were most numerous in the sorghum-sudangrass seed and corn ear baits. In the second year, M. communis larvae were more numerous in food baits than in soil samples, and more numerous in the oatmeal-corn flake and rolled oat baits than in other food baits. Numbers of Conoderus spp. larvae did not differ between food bait and soil samples nor among food baits. In addition to attracting more wireworms, oatmeal-corn flake and rolled oat baits had some of the shorter processing times. The use of one of these two baits is currently recommended for pre-plant sampling of wireworms in potato fields in southern Florida. /// Se hicieron experimentos antes de la siembra durante dos temporadas de crecimiento consecutivos para evaluar cebos como muestreo de gusanos de alambre que atacan la papa en el sur de la Florida. Las especies estudiadas fueron: Melanotus communis (Gyllenhal), Conoderus falli Lane, C. amplicollis (Gyllenhal, y C. rudis (Brown). Los cebos evaluados fueron semilla de un híbrido de maíz dulce, semilla de un híbrido de sorgo-hierba de sudán, una mezcla 1:1 de semilla de maíz y sorgo-hierba de sudán, una mazorca completa de maíz dulce, pedazos de semillas de papa, una mezcla de 1:1 de harina de avena y copos de maíz, avena \"enrollada\", y zanahorias. En el primer año, no hubo diferencia en el número de gusanos de alambres entre los cebos y las muestras de tierra en la mayoría de las cebos probados. Larvas de Melanotus communis fueron más numerosas en los cebos de harina de avena-copos de maíz y en semillas de sorgo-hierba de sudán. Larvas de Conoderus spp. fueron más numerosas en semillas de sorgo-hierba de sudán y en mazorcas completas de maíz. En el segundo año, larvas de M. communis fueron más numerosas en cebos que en muestras de suelo, y más numerosas en la harina de avena-copos de maíz y en avena \"enrollada\" que en otros cebos. No hubo diferencia en el número de larvas de Conoderus spp. entre los cebos y las muestras de tierra, ni entre los cebos. Aparte de que atrayeron más gusanos de alambre, cebos de harina de avena-copos de maíz y de avena \"enrollada\" tuvieron uno de los tiempos más cortos de procesamiento. Se recomienda el uso de uno de estos dos cebos para el muestreo de gusanos de alambre antes de la siembra de papas en el sur de la Florida.

Stand reductions in plant cane caused by Melanotus communis (Gyll.) were quantified in small-plot tests with 2 commercial clones and in a large-plot study with 1 commercial clone. A standard measure of the number of wireworms per 1.5 row-meters was used. Infestation levels studied ranged from 0 up to 12 M. communis per 1.5 row-m. Stand reductions per wireworm per 1.5 row-meters ranged from 6.2 to 7.8% at 12 weeks after planting based on regression analyses. Tillering during the growing season compensated to some degree for early stand losses but, at harvest, stalks from plots infested by wireworms tended to weigh less. Yield in terms of the total weight of cane in plots at harvest was reduced by wireworms. In the large-plot study, the weight of cane harvested per hectare was reduced by 5.9 metric tons or by 3.8% per wireworm per 1.5 row-meters (r = .92). Wireworms did not cause reductions in sucrose levels in juice. However, because cane weight at harvest was reduced by 3.8% per wireworm per 1.5 row-meters, the amount of sugar produced was reduced by the same amount. Stand reductions in plant cane caused by 8 to 12 wireworms/1.5 row-meters carried over into the first ratoon crop, which resulted in lower yield of the ratoon crop. /// Se cuantificaron las pérdidas en la reducción de plantas en caña de plantilla causadas por Melanotus communis (Gyll.) en el campo en pequeñas parcelas con dos clones comerciales y en un estudio con una parcela grande de un clon comercial. Se usó la medida patrón de gusanos de alambre en 1.5 metros de zurco. La disminución en el número de plantas por cada gusano de alambre en 1.5 metros de zurco fluctuó entre 6.2 y 7.8% basado sobre datos de un análisis de regresión del número de plantas contadas a las 12 semanas después de la siembra. El macollamiento durante la temporada de crecimiento compensó, hasta cierto punto, la pérdida de plantas, pero los tallos de parcelas infestadas por gusanos de alambre tendieron a pesar menos cuando se cosecharon. El rendimiento en términos del peso total de la caña en parcelas fue reducido por los gusanos de alambre. En el estudio de la parcela grande, el peso por hectarea de la caña cosechada se redujo un 3.8% por cada gusano de alambre en 1.5 metros de zurco (r = .92). Los gusanos de alambre no causaron reducción en los niveles de sacarosa del jugo en estas pruebas. Sin embargo, debido a que el peso de la caña fue reducido un 3.8% por cada gusano de alambre en 1.5 metros de zurco, la cantidad de azúcar se redujo por la misma cantidad. La reducción de plantas en caña plantilla causada por 8 a 12 gusanos de alambre en 1.5 metros de zurco en el estudio de la parcela grande, también afecto el cultivo de primer retoño.

M. communis (Gyllenhal) is the most prevalent wireworm species in south Florida (Wilson 1940) and is an important pest of both vegetable and field crops in this area (Genung 1972). Soil insecticides are commonly used in may crops to prevent damage by M. communis . Comparative tests have not been conducted on the toxicity of different insecticides to M. communis , probably due to the difficulties involved in obtaining a large number of wireworms needed for such tests. In this study, the authors evaluated the contact toxicities of eight insecticides to M. communis wireworms.