Feeding Injury Research Articles

Preliminary Approach in Detecting Cotton Fleahopper Induced Damage Via Unmanned Aerial Systems and Normalized Difference Vegetation Indices

The use of unmanned aircraft systems (UAS) delivering imaging technologies in agricultural settings has become more prevalent over the past five years and is growing in pest management programs. Here, spectral data from a three-band consumer-grade camera with a filter to obtain Near Infrared (NIR) data, mounted on a fixed-winged UAS, was used to assess the ability to detect cotton fleahopper, Pseudatomoscelis seriatus (Reuter) (Hemiptera: Miridae), injury to immature fruiting bodies on cotton. In a small plot experiment conducted two years and two planting periods each year, cotton fleahopper densities were manipulated with insecticide. Variable populations of cotton fleahopper across the plots were achieved in 2015, ranging between 0 and 3.5 cotton fleahopper-days over a five-week period when squares were forming. Derived from spectral data of multiple UAS flights, unexpected but inconsistent trends (by regression analysis) of increasing Normalized Difference Vegetation Index (NDVI), values with increasing cotton fleahopper days were detected in both plantings and years (five of 12 regressions were significant). Our preliminary data suggest that differences in cotton fleahopper activity on cotton may be reflected in NDVI values using a modified consumer-grade camera in-season. But the interpretation of NDVI may be complicated by the feeding site of cotton fleahopper, leading to unexpected and inconsistent regressions. Exploration of image resolution and bandwidth to define optical sensor needs appears important for cotton fleahopper, given its feeding habitat and injury to cotton. The application of UAS-derived remotely sensed data to detect insect-induced plant stress continues to have merit, but a merging of best suited UAS technology to the needs of detecting insect-induced cotton stress will be a research-intensive endeavor.

Horn Fly (Diptera: Muscidae)—Biology, Management, and Future Research Directions

AbstractThe horn fly, Haematobia irritans irritans (L.), is one of the most important external parasites of cattle in North America and elsewhere. Horn fly adults have an intimate association with cattle, their primary host. With their often-high numbers and by feeding up to 38 times per day per fly, horn flies stress cattle. The resulting productivity loss is valued at more than 2.3 billion USD in the United States. Insecticides are commonly used to mitigate direct injury from feeding and indirect injury from disease transmission. This paper discusses horn fly biology, distribution, and management. Emphasis is on promising new approaches in novel insecticides, repellents, biological control, vaccines, animal genetics, and sterile insect technology that will lead to effective preventative tactics and the integration of smart technologies with horn fly management. We conclude with a discussion of research needs necessary to shift horn fly integrated pest management to an emphasis on preventative tactics and the precision use of reactive techniques.

Effect of thiamethoxam seed treatment in peanut

AbstractTobacco thrips (Frankliniella fusca) and tomato spotted wilt (TSW) orthotospovirus (family Tospoviridae, genus Orthotospovirus) can reduce peanut (Arachis hypogaea L.) yield. Systemic insecticides are applied in the seed furrow at planting and to peanut foliage to reduce injury from tobacco thrips and decrease incidence of TSW. Research was conducted in Georgia, North Carolina, South Carolina, and Virginia in 2013 and 2014 to compare the effect of the following treatments on tobacco thrips feeding injury and expression of TSW in peanut: thiamethoxam seed treatment, thiamethoxam seed treatment followed by acephate 3 weeks after planting, phorate applied in the seed furrow at planting, and a nontreated check. Tobacco thrips feeding injury and TSW incidence were significantly higher in thiamethoxam and thiamethoxam followed by acephate‐treated peanut than peanut treated with phorate. Thiamethoxan seed treatment followed by acephate resulted in significantly lower tobacco thrips feeding injury compared to thiamethoxam seed treatment alone. Yield of Virginia market type cultivars was greater when thiamethoxam was followed by acephate applied to peanut foliage or when phorate was applied compared with nontreated peanut or the seed treatment alone. Runner market type cultivars yielded higher when phorate was applied compared with nontreated peanut while peanut treated with thiamethoxam with or with acephate yielded similar to both of these treatments.

Spatial and genetic crop diversity support ecosystem service delivery: A case of yield and biocontrol in Dutch organic cabbage production

• We developed and validated a diagrammatic scale to assess herbivore leaf-feeding injury in cabbage. • We used an experimental network of seven intercropping designs. • Crop diversification via intercropping reduced herbivore feeding injury in cabbage. • Lower injury was observed with the presence of a within-field functional flower strip. • Individual and total yields were maintained in five out of seven intercropping designs. A single focus on yield in agroecosystems comes at the expense of other ecosystem services, for instance, biocontrol of pests. In this study, we investigated the potential of intercropping to improve the delivery of ecosystem services by cropping systems. Intercropping was expected to deliver a higher yield through facilitation and complementarity while simultaneously suppressing pests via pest habitat dilution and habitat provision for natural enemies. Utilizing a network of experiments on crop diversification with different spatial arrangements and different levels of genetic crop diversity across the Netherlands in 2018, we analyzed the effect of seven intercropping designs on crop injury by pests, yield and quality in cabbage. Individual cabbage leaf injury by herbivorous pests was assessed using a newly developed diagrammatic scale. Provisioning services were measured as individual cabbage fresh weight and yield per unit area. We found a significant negative relationship between crop diversity and herbivore feeding injury per cabbage: intercropping designs with more species, accessions and/or cultivars exhibited lower feeding injury. The presence of flower strips significantly reduced overall injury in the adjacent cabbage strip, despite higher injury found in the rows closer to the flower strip. There was no clear relationship between crop diversity and fresh marketable weight per cabbage, however five out of seven intercropping designs were able to maintain total yield per area when compared with the sole crop reference. Our results show that crop diversification can simultaneously support the production ecosystem service by maintaining fresh marketable weight per cabbage plant and productivity per unit area, as well as the regulating ecosystem service of pest control. These results provide a basis for redesigning large-scale arable fields into diversified productive systems, and thereby facilitate the transition towards more sustainable farming systems. A better understanding of crop functionality and management needs in diverse arrangements is relevant for such redesign.

The Short-Range Movement of Scirtothrips dorsalis (Thysanoptera: Thripidae) and Rate of Spread of Feeding Injury Among Strawberry Plants.

Scirtothrips dorsalis Hood infest strawberry (Fragaria x ananassa Duchesne, Rosaceae) fields from nearby crop fields and surrounding vegetation and cause injury to plants by feeding on young leaf tissues. Greenhouse and field studies were conducted to determine the short-range movement of S. dorsalis to assess the risk of an early S. dorsalis population to spread to adjacent plants. In a greenhouse, 25 potted strawberry plants were arranged in two concentric rows around a central plant, where plants in inner rows were 20 cm, and those in the outer rows were 40 cm from the central plant. In the field, 20 strawberry plants were arranged in two beds (90 cm apart), ten in each bed, and five plants in each row, with plants 30 cm apart. White sticky cards were placed at 60-120 cm from the central plant. Fifty S. dorsalis adults were released on a centrally located plant, and the numbers of S. dorsalis adults and larvae and feeding injury were recorded for 9-17 d on adjacent plants and sticky cards. Results showed that significantly more S. dorsalis adults and larvae remained on the initially infested plant compared to adjacent plants, although few adults were found up to 120 cm on sticky cards. The rate of spread of feeding injury was low with slight bronzing injury (<10% injury) on adjacent plants by 14-17 d. Since most S. dorsalis remained on initially infested plants for at least 2 wk, it is feasible to delay management actions and 'rescue' plants around a plant with minor injury symptoms.

Gibberellic acid decreases Melanocallis caryaefoliae (Hemiptera: Aphididae) population density and chlorotic feeding injury to foliage in pecan orchards.

Melanocallis caryaefoliae (Davis), Monellia caryella (Fitch), and Monelliopsis pecanis Bissell (Hemiptera: Aphididae) attack pecan foliage (Carya illinoinensis [Wangenh.] K. Koch). Unlike M. caryella and M. pecanis, feeding by M. caryaefoliae triggers a physiological change within foliage mimicking natural leaf senescence; it can lead to defoliation. Pretreatment of pecan foliage with gibberellic acid (GA3 ) mitigates M. caryaefoliae-elicited physiological disturbances. GA3 application to pecan was evaluated for efficacy regarding effects on M. caryaefoliae populations and possible negative side-effects on two natural enemy species and on return bloom of pecan. All GA3 treatment rate schedules significantly reduced M. caryaefoliae nymphs but not adults or adults and nymphs of M. caryella or M. pecanis. Percentage leaf chlorosis elicited by M. caryaefoliae was significantly reduced by GA3 (i.e., 39.5 to 197.7 g a.i./ha). No negative side-effects of GA3 treatment were detected regarding certain key natural enemy species or on return bloom of pecan. Application of GA3 to the orchard canopy protects foliage from senescence-like physiological responses triggered by M. caryaefoliae. This reduces detrimental leaflet chlorosis, both senescence and abscission processes and horticulturally significant feeding injury. Additionally, the absence of apparent negative side-effects on key natural enemies and return bloom is suggestive of a practical means for efficacious non-insecticidal control of M. caryaefoliae populations in orchards. This novel protective effect of GA3 against aphid-elicited, senescence-like physiological responses may merit investigation as an IPM tool to manage aphid species eliciting similar senescence-like damage to other crop species. Published 2020. This article is a U.S. Government work and is in the public domain in the USA.

Fusarium Hardlock Associated With Lygus lineolaris (Hemiptera: Miridae) Injury in Southeastern Cotton.

The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), is an important insect pest in cotton that feeds on reproductive fruit, contributing to yield loss. Economically damaging infestations of L. lineolaris have doubled in Virginia since 2013. Escalation of L. lineolaris abundance may increase Fusarium hardlock disease observed in this region, compounding economic losses. Research has linked Fusarium hardlock with fungal species Fusarium verticillioides and F. proliferatum. Field and greenhouse experiments were performed to investigate (i) Fusarium hardlock occurrence in field plots managed and unmanaged for L. lineolaris, (ii) severity of F. verticillioides infection of cotton bolls with and without the presence of L. lineolaris feeding in a greenhouse setting, and (iii) Fusarium species composition and prevalence within field-collected L. lineolaris and cotton lint with and without insect feeding injury and hardlock symptoms present. Nearly twice the amount of hardlock (i.e., proportion of hardlocked locules) occurred in field-collected bolls with L. lineolaris feeding symptoms (0.40 ± 0.02) compared with bolls without (0.21 ± 0.01). Based on real-time quantitative PCR, cotton bolls exposed to F. verticillioides inoculum and caged with L. lineolaris adults had greater levels of F. verticillioides DNA compared with untreated bolls. F. proliferatum, F. verticillioides, and F. fujikuroi were isolated from field-collected L. lineolaris and hardlocked cotton lint at harvest. These findings suggest that the presence of L. lineolaris is associated with an increased risk of Fusarium hardlock in Southeastern cotton, and both should be carefully managed using timely insecticide applications and cultural control practices to minimize yield loss.

Evaluation of a 'Preventative' Strategy to Manage Spider Mites on Almond.

Simple SummaryThe almond industry in California produces approximately 80% of the world’s supply and currently consists of roughly 0.45 million bearing and non-bearing hectares. Spider mite management is a component of annual arthropod management strategies on almond. Regularly, acaricides containing the active ingredient, abamectin, are applied in spring when mites are not yet present or well below a level which justifies treatment, in other words applied to prevent rather than treat existing populations. Although other acaricides are used, those containing the active ingredient, abamectin, accounted for 68% to 95% of spring (preventative) applications between 2005 and 2017. Although the strategy is widely employed in the almond industry, there are no published studies supporting the practice. Moreover, the strategy runs contrary to sustainable, integrated pest management practices by forgoing monitoring, reliance on spider mite natural enemies, and economic threshold levels. In this study, we conducted large field trials to evaluate the effectiveness of preventative acaricide applications. Results showed that farmers can forego a preventative strategy since spider mite densities typically remain well below damaging levels through the period critical for tree growth and nut yield. Also, results showed that such a heavy reliance on abamectin has led to a low to moderate level of resistance developing in some spider mite populations in the southern and mid San Joaquin Valley.Field experiments were conducted in two commercial almond orchards located in the southern San Joaquin Valley during 2016 and 2017 to evaluate a “preventative” strategy to manage spider mites. Pacific mite, Tetranychus pacificus McGregor, was identified as the only mite species infesting the experimental sites in both years. We monitored mites weekly in 3.6-hectare plots over approximately 21 weeks in 2016 and in 2017 using guidelines developed by the University of California. In late May, prior to the detection of mites, preventative acaricide treatments, abamectin, cyflumetofen, or etoxazole were applied to the experimental plots at a field rate. In 2016 and 2017, mite densities in all the treatments increased at early-July, peaked at mid-August, and were undetectable by late August. Preventative acaricide-treated plots in 2016 tended to have significantly lower mite densities than in the untreated control plots. Although in 2017, densities in the acaricide-treated plots tended to not significantly differ from control plots. Mite feeding injury, measured as mean cumulative mite-days, did not exceed the economic threshold during the experiment. The biological control agent, sixspotted thrips, Scolothrips sexmaculatus (Pergande) likely played a role in controlling mite populations at mid and late August. Our results indicate that a preventative strategy does not play a definitive role in T. pacificus management on almond. Additionally, acaricides with the active ingredient, abamectin, are heavily relied on as preventative treatments. We assessed populations of T. pacificus from the mid and southern San Joaquin Valley and found increased tolerance to a medium level of resistance to the acaricide.

Characterizing the Feeding Injury Caused by Phylloscelis rubra (Hemiptera: Dictyopharidae) to Cranberries.

Due to changes in pest management practices, farmers’ reports of severe feeding injury to cranberries, Vaccinium macrocarpon Aiton Ericales: Ericaceae, caused by the cranberry toad-bug, Phylloscelis rubra Ball, have increased in recent years in New Jersey (United States). Currently, however, limited information is available on the effects of P. rubra feeding or density of individuals needed to cause injury to cranberry vines and fruit. In 2015‒2017, we conducted studies to characterize injury to cranberry at a range of P. rubra densities by using cages in a screen-house and field, to establish a correlation between P. rubra density and crop injury in an open field experiment, and to measure the effects of P. rubra injury on the nutritional content (i.e., amounts of macro- and microelements) of cranberry vines. Phylloscelis rubra feeding on cranberry vines produced typical injury symptoms at relatively low densities (i.e., 2 individuals per vine in field cages or <10 individuals per sweep net sample in open fields), which included discolored (yellowish or reddish) or dead (brown) vines. This vine injury could lead to reductions in fruit mass and total fruit number. However, P. rubra injury to cranberry vines did not alter their nutritional composition. In general, this study highlights the ability of P. rubra to cause substantial injury to cranberry vines even when population densities were relatively low, which could result in declines in fruit production (quality and quantity). Therefore, infestations by P. rubra in cranberries must be considered when making pest management decisions in regions where this insect is present.

Reevaluating the Economic Injury Level for Brown Stink Bug (Hemiptera: Pentatomidae) at Various Growth Stages of Maize.

Economic yield loss and reduction in grain quality from brown stink bug, Euschistus servus (Say), feeding injury in early and late stages of maize, Zea mays (Poales: Poaceae, Linnaeus), development was assessed in Virginia and North Carolina in 2018 and 2019. Varying levels of stink bug infestations were introduced to seedling maize (V2-early stage), and a range of late-stages of maize, including 1) the last stage of vegetative development (V12/V14), 2) prior to tasseling, 3) at tasseling (VT), and 4) across all tested late growth stages. Euschistus servus infestation levels included 33, 67, and 100% of maize seedlings, and 25, 50, 100, and 200% of plants during later stages. Infestations were maintained on seedling maize for 7 d, and 8 or 16 d in reproductive stages. Infestation level in seedling maize had an impact on grain yield. Infestation level and growth stage both had an impact on grain yield in reproductive maize. The percentage of discolored kernels was also affected by infestation level, but not growth stage. Regression analysis between grain yield and infestation level indicated that the average economic injury level is 7% in seedling maize (7 bugs/100 plants) and 12% (12 bugs/100 plants) from the last vegetative stages (V12/V14) through pollination (VT). The economic injury level in the late vegetative stages is only applicable when infestations are present for an extended period of time (16 d), emphasizing the need for continued scouting of maize throughout the season to make informed management decisions.

Susceptibility of the bird cherry‐oat aphid, Rhopalosiphum padi (Hemiptera: Aphididae), to four insecticides

AbstractThe bird‐cherry oat aphid (Rhopalosiphum padi) is a global pest, attacking most cereal crops including barley, wheat, oats and triticale. The aphids cause yield losses through direct feeding damage and the transmission of plant viruses. In Australia, feeding injury can reduce cereal yields by 6%, with the damage caused by aphid‐vectored viruses reducing the yield of cereal crops by up to 30%. Aphid control in these crops is achieved almost exclusively with insecticides, and there is growing concern surrounding insecticide resistance evolution in multiple aphid species. In this study, nine field populations of R. padi were collected from localities representing the major grain growing regions of Australia. Toxicity data against four insecticides (dimethoate, alpha‐cypermethrin, pirimicarb and imidacloprid) was generated for each aphid population. This revealed little differences in population responses for three of these insecticides. For alpha‐cypermethrin, a widely used insecticide in Australia, there were significant differences between several populations. These data will be important for future monitoring of insecticide responses of R. padi and highlight the impending pest management challenges growers could encounter in Australia.

Antixenosis, Antibiosis, and Potential Yield Compensatory Response in Barley Cultivars Exposed to Wheat Stem Sawfly (Hymenoptera: Cephidae) Under Field Conditions.

Wheat stem sawfly, Cephus cinctus Norton, is an economically serious pest of cereals grown in North America. Barley cultivars were previously planted as resistant crops in rotations to manage C. cinctus, but due to increasing levels of injury to this crop, this is no longer a valid management tactic in Montana. Therefore, we aimed to understand antixenosis (behavioral preference), antibiosis (mortality), and potential yield compensation (increased productivity in response to stem injuries) in barley exposed to C. cinctus. We examined these traits in eight barley cultivars. Antixenosis was assessed by counting number of eggs per stem and antibiosis was assessed by counting infested stems, dead larvae, and stems cut by mature larvae. Potential yield compensation was evaluated by comparing grain yield from three categories of stem infestation: 1) uninfested, 2) infested with dead larva, and 3) infested cut by mature larva at crop maturity. We found the greatest number of eggs per infested stem (1.80 ± 0.04), the highest proportion of infested stems (0.63 ± 0.01), and the highest proportion of cut stems (0.33 ± 0.01) in ‘Hockett’. Seven out of eight cultivars had greater grain weight for infested stems than for uninfested stems. These cultivars may have compensatory responses to larval feeding injury. Overall, these barley cultivars contain varying levels of antixenosis, antibiosis, and differing levels of yield compensation. Our results provide foundational knowledge on barley traits that will provide a framework to further develop C. cinctus resistant or tolerant barley cultivars.

Eicosapentaenoic acid-containing polar lipids from seaweed Susabinori (Pyropia yezoensis) alleviate hepatic steatosis in obese db/db mice

Nonalcoholic fatty liver disease (NAFLD) is emerging as the most common liver disease in industrialized countries. Because hepatic steatosis is an early pathogenesis of NAFLD, the discovery of food components that could ameliorate hepatic steatosis is of interest. Susabinori (Pyropia yezoensis) is recognized as one of the most delicious edible brown algae, and we prepared lipid component of susabinori (SNL), which is rich in eicosapentaenoic acid (EPA)-containing polar lipids. In this study, we tested whether feeding SNL to db/db mice protects them from developing obesity-induced hepatic steatosis. After four weeks of feeding, hepatomegaly, hepatic steatosis, and hepatic injury were markedly alleviated in SNL-fed db/db mice. These effects were partly attributable to the suppression of activities and mRNA expressions of lipogenic enzymes and enhanced levels of adiponectin due to the SNL diet. Additionally, mRNA expression of monocyte chemoattractant protein-1, an inflammatory chemokine, was markedly suppressed, and the mRNA levels of PPARδ, the anti-inflammatory transcription factor, were strongly enhanced in the livers of db/db mice by the SNL diet. We speculate that the development and progression of obesity-induced hepatic steatosis was prevented by the suppression of chronic inflammation due to the combination of bioactivities of EPA, phospholipids, and glycolipids in the SNL diet.

Low Tunnels Reduce Insect Populations, Insecticide Application, and Chewing Insect Damage on Brussels Sprouts.

Low tunnels covered with spun-bonded fabric (row covers) provide season extension for vegetable production and also afford a physical barrier against airborne insects and other non-soil pests. Brussels sprouts, Brassica oleracea L. group Gemmifera (Brassicaceae), is a popular vegetable in local markets in Virginia; however, unprotected field production is severely affected by insect pest infestation. This study's objective was to determine the level of protection low tunnels provide against insect infestation and leaf herbivory injury. The experiment was conducted at the Virginia Tech Eastern Shore Agricultural Research and Extension Center in Painter, Virginia. The experimental design was split-plot with polyethylene soil mulches (white or black) as whole plot factors and production systems (low tunnel or open field) as subplot factors. In this study, low tunnels reduced insect infestation and chewing herbivory leaf injury to Brussels sprouts. Compared to an unprotected open field, infestations of lepidopteran insects and harlequin bug, Murgantia histrionica (Hahn) (Hemiptera: Pentatomidae) were reduced on plants under low tunnels. However, aphids (Hemiptera: Aphidae) infestation occurred under low tunnels in fall. There was no effect of color mulches (white or black) and no interaction between tunnel and mulch color on insect infestation and chewing injury. Fewer insect infestations and feeding injury indicate that low tunnels can be an effective management tool for sustainable vegetable production.

Efficacy of Bacillus thuringiensis (Bt) maize expressing Cry1F, Cry1A.105, Cry2Ab2 and Vip3Aa20 proteins to manage the fall armyworm (Lepidoptera: Noctuidae) in Brazil

Recommendations to manage the impact of Spodoptera frugiperda (Lepidoptera: Noctuidae) to maize production include the use of Bt crops where approved, combined with the adoption of integrated pest management (IPM) and insect resistance management (IRM) practices. This study evaluated the efficacy of Bt maize expressing proteins Cry1F + Cry 1A.105 + Cry2Ab2 + Vip3Aa20 to control S. frugiperda under field conditions in Brazil. This Bt maize technology effectively managed seedling cutting injury, significantly reduced foliar feeding and achieved near 100% protection from kernel-feeding caused by both a Cry1F-resistant strain and a field-collected population of S. frugiperda. Consistent field-collected data across several years and planting regions suggest that this Bt maize technology will be an important tool for the effective management of all important feeding injury types caused by S. frugiperda in Brazil. As with any Bt maize hybrid, its implementation within IPM and IRM practices should help growers maintain maize crop sustainability in Brazil.

Methods for Creating Medium and Large Animal Models of Peripheral Atherosclerosis

Atherosclerosis (AS) is the main pathological basis for the occurrence of many vascular diseases and has a strong association with metabolic syndrome. Peripheral arterial diseases caused by AS have high morbidities and mortalities but lack still effective treatment. AS animal models are highly valuable for research on peripheral arteriosclerotic diseases. While small and medium AS animal models based on high-fat feeding and balloon injuries have been successfully established,few literatures have described the creation of large animal models for AS treatment. This article elucidates the current methods for creating medium and large animal models of peripheral atherosclerotic disease,with an attempt to further promote the clinical translation of AS treatment research.

Pest potencial of Sitophilus zeamais on Brazil nut under storage conditions

The Brazil nut, fruit of Bertholletia excelsa H.B.K., a native plant of the Amazon region and may be considered one of the main extractivist products of countries like Bolivia, Colombia, Guyana, Venezuela, Peru and Brazil. In Brazil this plant can be found in the states of Acre, Amapá, Amazonas, Mato Grosso, Pará, Rondônia, Roraima and Tocantins. Species of the Coleoptera and Lepidoptera, have been classified as pest potentials of Brazil nut under storage conditions. Sitophilus zeamais (Coleoptera: Curculionidae) is one of the main insect pests attacking grain stores worldwide. This specie may be observed attacking grains in the field and in storage facilities (cross-infestation), presenting a wide variety of hosts. The purpose of this study was to assess the potential of adults of this species feed on Brazil nuts, and also to identify the type of injury as well as the life span of this coleopteran exposed to the meat of the Brazil nut. No feeding injury was observed on the surface of Brazil nuts and the life span of the insects was similar in treatments both with and without this food source in all populations evaluated. Due to the fact that S. zeamais adults do not injure, or feed on the Brazil nut, this beetle is not able to colonize this product and therefore may be considered a non-pest insect for stored Bertholletia excelsa almonds stored.

Acceptability of Bedding Plants by the Leatherleaf Slug, Leidyula floridana (Mollusca: Gastropoda: Veronicellidae)

Leidyula floridana (Leidy) (Gastropoda: Veronicellidae) has long been known to be a plant pest in the Caribbean region and southern Florida, though its range has expanded to include northern Florida, other Gulf Coast states, and Mexico. It is nocturnal, and often overlooked as a source of plant damage. Although polyphagous, it does not feed on all plants, and it is desirable to know what bedding plants will likely be damaged by this common herbivorous slug. To identify readily accepted bedding plants, I conducted a series of comparative trials of 7 d duration to assess the acceptance of 30 commonly grown bedding plants relative to French marigold, a plant that is commonly fed upon by slugs and snails. Several commonly grown bedding plants were shown to be very susceptible to feeding injury. In a second set of 7-d trials, I compared 14 plants from among those that were not readily accepted in the first set of trials to determine if they would remain poorly accepted when not provided with favored food. In the second set of trials, the levels of herbivory shown in the first trials were maintained, demonstrating that some bedding plants are not acceptable to L. floridana even when the slugs do not have access to acceptable food. Thus, a list of readily available bedding plants that resist herbivory by this slug has been determined, providing gardeners with slug-resistant choices. The most unacceptable species (damage rating = 1.00) were: lantana (Lantana camara L.; Verbenaceae), tickseed (Coreopsis spp.; Asteraceae), torenia (Torenia fournieri Linden ex E. Fourn.; Linderiaceae), angelonia (Angelonia angustifolia Benth.; Plantaginaceae), and snapdragon (Antirrhinum majus L.; Plantaginaceae). Additional plant species that were not very acceptable (damage rating of between 1.00 and 1.50) were blue daze (Evolvulus glomeratus Choisy; Convolvulaceae), dusty miller (Centaurea cineraria [L.] Jacq. ex Nym.; Asteraceae), viola (Viola hybrid; Violaceae), celosia (Celosia argentea L.; Amaranthaceae), and geranium (Geranium spp.; Geraniaceae). In contrast, plant species that seem to be at considerable risk of damage (damage rating 3 to 5) by L. floridana were: French marigold (Tagetes patula L.; Asteraceae), Madagascar periwinkle (Catharanthus roseus [L.] G. Don; Apocyanaceae), coleus (Plectranthus scutellarioides [L.] R. Br.; Laminaceae), petchoa (Petunia × Calibrachoa; Solanaceae), zinnia (Zinnia elegans Jacq.; Asteraceae), polka dot plant (Hypoestes phyllostachya Baker; Acanthaceae), chrysanthemum (Chrysanthemum morifolium Ramat; Solanaceae), petunia (Petunia spp.; Solanaceae), Stokes' aster (Stokesia laevis [Hill] Greene; Asteraceae), scarlet sage (Salvia splendens Sellow ex Nees; Lamiaceae), butter daisy (Melampodium paludosum Kunth; Asteraceae) and verbena (Verbena spp.; Geraniaceae). A few species were intermediate in susceptibility, namely: impatiens (Impatiens hawkeri W. Bull; Balsamaniaceae), wax begonia (Begonia × Semperflorens × Cultorum; Begoniaceae), sweet potato vine (Ipomoea spp.; Convolvulaceae), firecracker flower (Crossandra infundibuliformis [L.] Nees; Acanthceae), sweet William (Dianthus barbatus L.; Caryophyllaceae), pansy (Viola × Wittrochinana; Violaceae), purslane (Portulaca oleraceae L.; Portulacaceae), and alyssum (Lobularia maritima [L.] Desv.; Brasscaeae).

Beet Armyworm Spodoptera exigua: Emerging Threat to Onion Production

Beet armyworm Spodoptera exigua Hubner (Lepidoptera: Noctuidae), hitherto a minor pest, had already taken a heavy toll on onion production. Regular monitoring of onion during 2017, for the S. exigua occurrence, revealed severe defoliation by this pest at the experimental farm in ICAR-DOGR, Pune. During the first appearance, about 44.72% plants were damaged with lesser feeding injury, while at the later stage the damage raised up to 81.90%. About 5–8 larvae/leaf fold and 3–4 larvae in an umbel were recorded at peak infestation. Severely infested plots registered with 10–12% damaged bulb after harvest. Overall mean plant damage ranged from 70.0 to 81.90% in some popular rabi onion varieties. However, the damage percentage does not differ significantly among the cultivated varieties which clearly denote the susceptibility of all these varieties. In the coming years, it will undoubtedly be a big problem for all states where onion is an important crop. Hence, much attention is needed, especially on pest bio-ecology in the onion ecosystem, scope of present IPM strategies employed for managing other major pest, bio-control potential and identification of safer insecticides for effective management to avoid yield loss.

Impact of Various Bt Cotton Traits and the Application of an Insecticide on the Within Plant Distribution of Helicoverpa zea (Lepidoptera: Noctuidae) Larvae and Injured Floral Structures

Previous studies have indicated that the expression of insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) in cotton can have a significant influence on the behavior of bollworm larvae (Helicoverpa zea, Lepidoptera:Noctuidae). This suggests that the particular Bt protein produced by a cotton variety may need to be considered when determining the most ideal scouting methods to utilize for bollworm. NonBt, WideStrike (producing Cry1Ac + Cry1F Bt insecticidal proteins), and Bollgard II (Cry1Ac + Cry2Ab) cotton varieties were planted and either treated with an insecticide or left untreated. The presence of H. zea larvae and their feeding injury were recorded according to their location in the canopy and type of floral structure where they were found. Results from comparison of larval and injury distributions indicated no significant differences between the different cotton varieties tested, and that insecticide treatment had minimal impact on this distribution. Larval size was generally associated with location in the canopy, suggesting that larvae tend to move towards the middle of the canopy as they age. The effect of different Bt cotton technologies appears to associate with how quickly larvae move to preferred feeding sites rather than their preference for particular feeding sites. These results suggest that scouting methods could be standardized independently of the presence of a Bt cotton trait or previous insecticide application. Focusing scouting efforts on the middle portion of the canopy (i.e., nodes 6-9) should increase the detection of small larvae and ‘fresh’ injury and be less influenced by previous insecticide applications.