Effect of trichome density on soybean pod feeding by adult bean leaf beetles (Coleoptera: Chrysomelidae).

The role of soybean, Glycine max (L.) Merrill, pod trichomes on feeding by adult bean leaf beetles. Cerotoma trifurcata (Forster), was evaluated under laboratory and field conditions during 1997 and 1998. Three Clark isolines and 'Corsoy 79' were used to compare the feeding preference of the beetle on pods with different trichome densities. The three Clark isolines, including densely pubescent, sparsely pubescent, and glabrous, were isogenic except for trichome density. The trichome densities on the pods of Clark densely pubescent, Clark sparsely pubescent, and Corsoy 79 were significantly different. In no-choice tests, under both laboratory and field conditions, the feeding on pods of Clark densely pubescent was significantly lower than that on the other isolines. In the choice test of Corsoy 79 conducted in the laboratory and field, when the trichomes on one of the two pods were shaven off, the feeding on the shaven pods was significantly higher than that of the intact ones. In the choice test among Clark isolines under laboratory condition, the result was significant, with the lowest feeding on the densely pubescent pods. This study demonstrates that densely pubescent soybean has the potential to resist bean leaf beetle feeding on pods.     

Impact of planting date on sunflower beetle (Coleoptera: Chrysomelidae) infestation,damage, and parasitism in cultivated sunflower

The sunflower beetle, Zygogramma exclamationis (F.), is the major defoliating pest of sunflower (Helianthus annuus L.). Planting date was evaluated as a potential management tool in a variety of production regions throughout North Dakota from 1997 to 1999, for its impact on sunflower beetle population density of both adults and larvae, defoliation caused by both feeding stages, seed yield, oil content, and larval parasitism in cultivated sunflower. Results from this 3-yr study revealed that sunflower beetle adult and larval populations decreased as planting date was delayed. Delayed planting also reduced defoliation from adult and larval feeding, which is consistent with the lower numbers of the beetles present in the later seeded plots. Even a planting delay of only 1 wk was sufficient to significantly reduce feeding damage to the sunflower plant. Yield reduction caused by leaf destruction of the sunflower beetle adults and larvae was clearly evident in the first year of the study. The other component of sunflower yield, oil content, did not appear to be influenced by beetle feeding. The tachinid parasitoid, Myiopharus macellus (Rheinhard), appeared to be a significant mortality factor of sunflower beetle larvae at most locations regardless of the dates of planting, and was able to attack and parasitize the beetle at various larval densities. The results of this investigation showed the potential of delayed planting date as an effective integrated pest management tactic to reduce sunflower beetle adults, larvae, and their resulting defoliation. In addition, altering planting dates was compatible with biological control of the beetle, because delaying the planting date did not reduce the effectiveness of the parasitic fly, M. macellus, which attacks the sunflower beetle larvae.     

Bean leaf beetle (Coleoptera: Chrysomelidae) management for reduction of bean pod mottle virus

Bean pod mottle virus (BPMV) is a management concern for soybean, Glycine max (L.), producers in the North Central states because it can cause yield loss and reduce seed quality by induction of seed coat mottling. The main vector of BPMV is the bean leaf beetle, Cerotoma trifurcata (Forster). An experiment was conducted in 2000 and 2001 at two locations in northwestern and central Iowa to test three insecticide treatments for suppression of bean leaf beetles, and subsequently, BPMV. Treatments of insecticide applications with lambda-cyhalothrin were 1) a single early-season application (23 g [AI] /ha) (2.5 oz/acre) at the VE-VC soybean developmental stage; 2) two early-season applications, the first the same as treatment 1 and a second at the same rate 9-13 d later; 3) a single early-season application the same as treatment 1, followed by a mid-season application (28 g [AI] /ha (3.2 oz/acre) at approximately R2 (flowering, near 15 July); and 4) an unsprayed control. Application of lambda-cyhalothrin after soybean emergence and again as first-generation bean leaf beetles emerged in northwestern Iowa in 2000 (treatment 3) significantly reduced beetle densities through mid-season, BPMV field incidence by 31.5%, and seed coat mottling by 31.2%, compared with the unsprayed control. Similar effects were measured at the same location when insecticide was applied twice at early season (treatment 2). Yield was 453.7 kg/ha (6.74 bu/acre) greater in treatment 2 and 525.20 kg/ha (7.80 bu/acre) greater in treatment 3 than in the unsprayed control at the northwestern site in 2000. At both locations in 2001 fewer treatment effects were observed, which was likely related to lower beetle populations in that year. Early-season insecticide sprays targeted at overwintered beetles on VC-VE reduced the initial population of vector insects and may have contributed to a lower first-generation population because of reduced overwintered beetle oviposition. In 1 year at one location there was a benefit to an additional mid-season insecticide spray, although effectiveness of spraying at this time could vary based on the magnitude of the vector population.     

Evaluation of conventional resistance to European corn borer (Lepidoptera: Crambidae) and western corn rootworm (Coleoptera: Chrysomelidae) in experimental maize lines developed from a backcross breeding program

Plant resistance is a promising control method for the two most damaging insect pests of maize, Zea mays L.: the European corn borer, Ostrinia nubilalis (Hübner), and the western corn rootworm Diabrotica virgifera virgifera LeConte. Fifteen experimental lines of maize, derived from a backcross breeding program designed to introgress resistance to European corn borer from Peruvian maize into two U.S. Corn Belt adapted inbred lines, were evaluated for resistance to European corn borer and western corn rootwonrm. The experimental lines were in the second generation of backcrossing. All experimental lines were resistant to leaf blade feeding by European corn borer. These lines had low levels of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one, a chemical commonly associated with leaf blade feeding resistance, indicating that this was not the mechanism of resistance to leaf blade feeding in these lines. Eleven experimental lines were resistant to leaf sheath and collar feeding by European corn borer. Useful sources of European corn borer ovipositional nonpreference and root feeding resistance to western corn rootworm were not identified. Some of the lines evaluated in this study may provide useful sources of resistance to both leaf blade and leaf sheath and collar feeding by European corn borer.     

Flight behavior of methyl-parathion-resistant and -susceptible western corn rootworm (Coleoptera: Chrysomelidae) populations from Nebraska

Relative flight behavior of methyl-parathion-resistant and -susceptible western corn rootworm, Diabrotica virgifera virgifera LeConte populations, was studied as part of a larger effort to characterize the potential impact of insecticide resistance on adult life history traits and to understand the evolution and spread of resistance. A computer interfaced actograph was used to compare flight of resistant and susceptible individuals, and flight of resistant individuals with and without prior exposure to methyl-parathion. In each case, mean trivial and sustained flight durations were compared among treatments. In general, there were few differences in trivial or sustained flight characteristics as affected by beetle population, insecticide exposure, sex, or age and there were few significant interactions among variables. Tethered flight activity was highly variable and distributions of flight duration were skewed toward flights of short duration. Tethered flight activity was similar among resistant and susceptible beetles with the exception that susceptible beetles initiated more flights per beetle than resistant beetles. After sublethal exposure to methyl-parathion, total flight time, total trivial flight time, and mean number of flights per resistant beetle declined significantly. Because long-range flight was uncommon, short- to medium-duration flights may play an important role in determining gene flow and population spread of resistant D. v. virgifera. These results suggest that organophosphate-resistant beetles can readily move and colonize new areas, but localized selection pressure (e.g., management practices) and exposure to methyl-parathion may contribute to the small-scale differences in resistance intensity often seen in the field.     

Consumption of residue containing cucurbitacin feeding stimulant and reduced rates of carbaryl insecticide by western corn rootworm (Coleoptera: Chrysomelidae).

Application of insecticide at a reduced rate with a cucurbitacin-based feeding stimulant is a viable alternative to a broadcast insecticide application for control of adult western corn rootworms, Diabrotica virgifera virgifera, LeConte. Because of the small amount of material applied, it is conceivable that a high density of beetles could consume all of the spray residue before economic control is achieved. A laboratory experiment was conducted to determine the amount of cucurbitacin-based spray residue consumed by beetles. Dried residue of four treatments were exposed to three groups of 10 rootworm beetles for 1 h each. Treatments consisted of a cucurbitacin-based adjuvant (Cidetrak CRW, Trécé, Salinas, CA) with carbaryl insecticide (Sevin XLR Plus, Rhone Poulenc, Research Triangle Park, NC) mixed at 0, 0.12, 1.2, and 12 g (AI)/liter. For the treatment with cucurbitacin adjuvant only (no insecticide), beetles consumed 0.029 mg beetle(-1) h(-1) of exposure. Approximately 54% of the beetles were recorded as feeding at any given time during the 60-min feeding period. However, when the spray residue contained carbaryl, no weight loss of treatment residue was measured, though the beetles were observed to feed from the residue during the first few minutes of exposure. When residue included insecticide, beetles quickly ceased feeding (within 20 min), and toxicity behavior was observed 30 min after initial exposure for up to 75% of the beetles, which were classified as moribund (unable to stand upright). Beetle mortality was recorded 24 h after exposure and demonstrated that male beetles (53% dead for three insecticide treatments) were more susceptible to carbaryl toxicity than female beetles (28% dead for three insecticide treatments). Regression analysis showed a significant positive relationship between mortality of female beetles and ovarian development. Based on the measurements of this experiment, it is unlikely that realistic beetle densities would consume enough spray residue to prevent economic control of the beetle population.     

Western corn rootworm (Coleoptera: Chrysomelidae) beetle emergence from weedy Cry3Bbl rootworm-resistant transgenic corn

Three greenhouse experiments were conducted to evaluate western corn rootworm, Diabrotica virgifera virgifera LeConte, beetle emergence from individual pots containing glyphosate-tolerant transgenic corn, Zea mays L., expressing the Cry3Bbl endotoxin from the soil bacterium Bacillus thuringiensis Berliner (MON863), nontransgenic glyphosate-tolerant isoline corn, grassy weeds (giant foxtail, Setariafaberi R.A.W. Herrm; and large crabgrass, Digitaria sanguinalis (L.) Scop.), and combinations thereof infested with 40 neonate larvae. In the first two experiments, pots with corn and weed combinations were treated with glyphosate 5 d after larval infestation to kill the weeds. The third experiment was similar to the first two except that untreated corn-weed combinations were added. In all three experiments beetle emergence varied significantly. Beetle recovery generally did not vary between the nontransgenic, nontransgenic + weeds, and MON863 + weeds. Significantly more beetles were recovered from MON863 + weeds than MON863 alone or weeds alone. Beetle emergence from MON863 + weeds was likely enhanced by larvae that initially survived on weeds before application of glyphosate. Preliminary data indicated that fecundity was highest from beetles reared on nontransgenic isoline corn and fewer eggs were laid by beetles reared on MON863 alone. Egg viability was generally lowest from beetles reared on MON863. The implications of these results in relation to insect resistant management are discussed.     

Imported longhorned weevil (Coleoptera: Curculionidae) injury to soybean: physiological response and injury guild-level economic injury levels

The imported longhorned weevil, Calomycterus setarius Roelofs, is an occasional pest of soybean, Glycine max (L.), and can cause substantial defoliation of seedling soybean when the weevil is present in large numbers. Because weevil populations can reach high levels, the potential exists for significant seedling injury, so economic injury levels (EILs) are needed for imported longhorned weevil on seedling soybean. Because the bean leaf beetle, Cerotoma trifurcata (Forster), also is present on seedling soybean, injury by this insect should be included in EIL calculations. This study was conducted to (1) determine daily soybean consumption rates of imported longhorned weevil; (2) compare soybean injury responses between weevil injured and noninjured soybeans; and (3) develop multiple species EILs for imported longhorned weevil and bean leaf beetle. Field and laboratory studies were conducted in 1997 to determine weevil daily consumption rates. Field experiments were conducted in 1998 to examine physiological responses of soybean to weevil injury. Field and laboratory consumption rates were 0.16 and 0.21 cm2 per day, respectively. There were no significant differences in physiological responses (i.e., photosynthetic rates, stomatal conductance, and transpiration rates) between noninjured soybean leaflets (caged) and weevil-injured leaflets. Multiple-species EILs were developed for imported longhorned weevil and bean leaf beetle on VC through V3 soybean.     

Comparison of adult corn rootworm (Coleoptera: Chrysomelidae) sampling methods

Studies were conducted in Kansas corn and soybean fields during 1997 to compare various sampling methods, traps, and trap components for capturing three species of adult corn rootworms: western (Diabrotica virgifera virgifera Leconte), southern (D. undecimpunctata howardi Barber), and northern (D. barberi Smith & Lawrence). Lure constituents affected the species of beetle attracted to the trap. Traps with a lure containing 4-methoxycinnamaldehyde attracted more western corn rootworms, those with a lure containing eugenol were more attractive to northern corn rootworms, and those containing trans-cinnamaldehyde were most attractive to southern corn rootworms. Multigard sticky traps caught more beetles than did Pherocon AM sticky traps. In corn, a newly designed lure trap caught more beetles than did sticky traps on most occasions. Also, lure-baited sticky traps caught more beetles than did nonbaited sticky traps. Varying the color of the lure trap bottom did not affect the number caught. In soybeans, the new lure traps captured more beetles than did the nonbaited Multigard or Pherocon AM sticky traps. Results of this study suggest the new lure trap may provide a more accurate assessment of corn rootworm populations than traditional monitoring techniques and may be more esthetically pleasing to growers and consultants.     

Field-Cage Studies of Beauveria bassiana (Hyphomycetes: Moniliaceae) for the Suppression of Adult Western Corn Rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae)

The efficacy of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin, was tested as a control agent for adult western corn rootworm, Diabrotica virgifera virgifera LeConte, in walk-in field cages. Suspensions of B. bassiana conidia were applied to corn plants in cages into which laboratory-reared beetles had been released. Beetles were collected at 3 and 5 days post-application and evaluated in the laboratory for mortality. Mortality was 10, 29 and 50%, at rate equivalents of 7 X 10 12 , 2 X 10 13 (two applications), and 5 X 10 13 conidia/ ha, respectively. There was no significant difference in mortality of beetles collected at 3 days compared with 5 days post-application. Mortality due to B. bassiana was 24% when beetles were released into field cages 24 h post-application (5 X 10 13 conidia/ha) compared with 50% when beetles were present during the application. Beetle mortality declined significantly with increasing time from application in feeding assays carried out with leaf samples removed from plants at 0, 12, 24 and 72 h post-application. Mortality of beetles collected from treated plants within cages and maintained in the laboratory was found to overestimate the population decline by 10% when compared with beetle estimates from treated plants within field cages.     

Evaluation of Cuphea as a rotation crop for control of western corn rootworm (Coleoptera: Chrysomelidae)

The ability to prevent significant root feeding damage to corn, Zea mays L., by the western corn rootworm, Diabrotica virgifera virgifera LeConte, by crop rotation with soybean, Glycine max (L.) Merr., has been lost in portions of the Corn Belt because this pest has adapted to laying eggs in soybean fields. Cuphea spp. has been proposed as a new broadleaf crop that may provide an undesirable habitat for rootworm adults because of its sticky surface and therefore may reduce or prevent oviposition in these fields. A 4-yr study (1 yr to establish seven rotation programs followed by 3 yr of evaluation) was conducted to determine whether crop rotation with Cuphea would provide cultural control of corn rootworm. In support of Cuphea as a rotation crop, fewer beetles were captured by sticky traps in plots of Cuphea over the 4 yr of this study compared with traps in corn and soybean, suggesting that fewer eggs may be laid in plots planted to Cuphea. Also, corn grown after Cuphea was significantly taller during vegetative growth, had significantly lower root damage ratings for 2 of 3 yr, and had significantly higher yields for 2 of 3 yr compared with continuous corn plots. In contrast to these benefits, growing Cuphea did not prevent economic damage to subsequent corn crops as indicated by root damage ratings > 3.0 recorded for corn plants in plots rotated from Cuphea, and sticky trap catches that exceeded the threshold of five beetles trap(-1) day(-1). Beetle emergence from corn plots rotated from Cuphea was significantly lower, not different and significantly higher compared with beetle emergence from continuous corn plots for 2002, 2003 and 2004 growing seasons, respectively. A high number of beetles were captured by emergence cages in plots planted to Cuphea, indicating that rootworm larvae may be capable of completing larval development by feeding on roots of Cuphea, although peak emergence lagged approximately 4 wk behind peak emergence from corn. Based on these data, it is unlikely that crop rotation with Cuphea will provide consistent, economical, cultural control of corn rootworm.     

Toxicity of Chromobacterium subtsugae to southern green stink bug (Heteroptera: Pentatomidae) and corn rootworm (Coleoptera: Chrysomelidae)

Diabrotica spp. (Coleoptera: Chrysomelidae) beetles and southern green stink bugs, Nezara viridula (L.) (Heteroptera: Pentatomidae), are pests on corn, Zea mays L., and soybean, Glycine max (L.) Merr., as well as on cucurbits. Control of these insects has depended on chemicals. An alternative to chemical control is the use of biologicals. Use of bacteria, fungi, viruses, pheromones, and metabolites to control these insects can potentially improve resistance management and reduce pesticide use. Other than Bacillus thuringiensis Berliner, few bacteria have been discovered that are lethal to either of these pests. Chromobacterium subtsugae Martin et al., a newly described bacterium that is known to be toxic to Colorado potato beetle, Leptinotarsa decemlineata (Say), larvae, was found to be toxic to both diabroticite adult beetles and southern green stink bug adults. In laboratory assays, toxins produced by these bacteria kill 80-100% of the adults of two species of diabroticite beetles, Diabrotica undecimpunctata howardi Barber and Diabrotica virgifera virgifera LeConte, and 100% of southern green stink bug adults within 6 d. For green stink bug, live bacteria were not needed for toxicity.     

Effects of pesticide applications and cultural controls on efficacy of control for adult Japanese beetles (Coleoptera: Scarabaeidae) on roses

Cultural and chemical controls were evaluated to determine their ability to deter feeding by Japanese beetles, Popillia japonica Newman (Coleoptera: Scarabaeidae), on floribunda type roses, Rosa 'Acadia Sunrise'. Roses were arranged in field plots and exposed to resident adult beetle populations. Cultural controls were designed to block the feeding-induced aggregation response by manually removing beetles and/ or damaged blooms from rose plants. Azadirachtin, carbaryl, and imidacloprid were evaluated in field and laboratory trials. In no-choice laboratory assays, foliar applications of azadirachtin caused low rates of morbidity to adult beetles and were unable to deter feeding. Foliar-applied carbaryl and soil-applied imidacloprid caused high rates of morbidity and reduced feeding injury. In the field, foliar sprays of azadirachtin and carbaryl, deterred feeding on foliage under low beetle pressure (maximum of 29% defoliation in untreated controls), when applied weekly after first beetle flight or every 2 wk after 5% injury was reached. A single foliar application of these materials at the 5% injury level did not significantly reduce peak defoliation. Soil applications of imidacloprid also deterred foliar feeding in the field. Blooms were more difficult to protect with both foliar- and soil-applied insecticides with only weekly application of foliar insecticides providing significant reductions in bloom injury. Removing beetles and/or blooms provided marginally greater reductions in leaf and flower injury. This suggests that blocking the feeding-induced aggregation response of Japanese beetles can provide only modest levels of control in roses where both flowers and feeding-induced volatiles recruit beetles to plants.     

Anatomical and nutritional factors associated with susceptibility of elms (Ulmus spp.) to the elm leaf beetle (Coleoptera: Chrysomelidae)

A wide range of susceptibility exists across elm (Ulmus) species and hybrids to the elm leaf beetle, Pyrrhalta luteola (Müller) (Coleoptera: Chrysomelidae). We evaluated various elm species, hybrids, or cultivars (taxa) growing in an experimental plantation in the city of Holbrook, AZ, for leaf anatomical (toughness and trichome density) and nutritional (minerals and sugars) traits that may be associated with host resistance. Leaf toughness and percentage of defoliation (susceptibility) were not correlated. However, we found weak negative correlations between percentage of defoliation and density of trichomes on the leaf abaxial surface. Of the 11 leaf nutrients examined, concentrations of iron and phosphorus correlated inversely with percentage of defoliation. The remaining nine traits did not show any correlation with percentage of defoliation. We concluded that individual anatomical and nutritional traits of elm species/hybrids do not seem to create a strong barrier to elm leaf beetle defoliation. However, the results from a stepwise multiple regression analysis indicated that collectively, these traits may play an important role in determining susceptibility.     

Evaluation of cucurbitacin-based gustatory stimulant to facilitate cucumber beetle (Coleoptera: Chrysomelidae) management with foliar insecticides in melons

The bitter plant-derived compounds cucurbitacins are known to stimulate feeding of adult cucumber beetles (Coleoptera: Chrysomelidae). A cucurbitacin-based gustatory stimulant applied as a flowable bait combined with either spinosad or carbaryl was compared with foliar sprays of spinosad and carbaryl for controlling two cucumber beetle species (Diabrotica undecimpunctata undecimpunctata Mannerheim and Acalymma trivittatum Mannerheim) in honeydew melons (Cucumis melo L.). Field studies were conducted on the University of California-Davis plant pathology farm in 2008 and 2009. Beetle densities after applications and fruit damage from beetle feeding were compared among treatments. In addition, beetle survival was compared within field cages placed over the treated foliage infested with beetles. Using all three measures of efficacy, we determined that the addition of cucurbitacin bait had no effect on the level of cucumber beetle control with carbaryl in either 2008 or 2009. In both years, spinosad did not significantly reduce cucumber beetle densities in either field cages or field plots and did not reduce fruit damage relative to the untreated control. The addition of the bait to spinosad did not improve its efficacy. A laboratory bioassay of the spinosad formulation used in the field showed it had significant lethal effects on adults of both cucumber beetle species. Results indicated that the bait formulation used did not improve cucumber beetle control but may benefit from the addition of floral attractants or using a different type of cucurbitacin.     

Increased Larval Growth and Preference for Virus-Infected Leaves by the Mexican Bean Beetle, Epilachna varivestis Mulsant, a Plant Virus Vector

Phaseolus vulgaris L. cv. 'Black Valentine' is a systemic host for the plant viruses Southern bean mosaic virus (SBMV) and bean pod mottle virus (BPMV). The Mexican bean beetle, Epilachna varivestis Mulsant, is a vector of SBMV and BPMV. Our objective was to determine if the interaction of SBMV and BPMV with 'Black Valentine' bean plants would affect beetle behavior and growth. In adult feeding preference test assays, beetles preferred and ingested more of the virus-infected bean leaf tissue than the noninfected leaf tissue. Beetle larvae that fed on SBMV- or BPMV-infected plants weighed more than those that fed on healthy plants. Our experiments suggest that there might be a mutually beneficial relationship between the beetle and the viruses that it vectors. The virus benefits from being transmitted and the beetle benefits from better larval growth when feeding on virus-infected leaf tissue. This study further demonstrates the complexity of relationships between multiple organisms.     

Characterization of general esterases from methyl parathion-resistant and -susceptible populations of western corn rootworm (Coleoptera: Chrysomelidae)

A consistent correlation between elevated esterase activity and methyl parathion resistance among Nebraska western corn rootworm, Diabrotica virgifera virgifera LeConte, populations has previously been documented. Characterization of general esterase activity using naphtholic esters as model substrates indicated that differences between resistant and susceptible strains could be maximized by optimizing assay conditions. The optimal conditions identified here were similar to those reported for other insect species. The majority of general esterase activity was found in the cytosolic fractions of resistant populations, whereas the activity was more evenly distributed between cytosolic and mitochondrial/nuclear fractions in the susceptible population. General esterase activity was predominately located in the adult thorax and abdomen. Although there were significant differences in general esterase activities between resistant and susceptible populations, the differences exhibited in single beetle activity assays did not provide sufficient discrimination to identify resistant individuals. In contrast, single larva activity assays provided greater discrimination and could be considered as an alternative to traditional bioassay techniques.     

Potential resistance of crape myrtle cultivars to flea beetle (Coleoptera: Chrysomelidae) and Japanese beetle (Coleoptera: Scarabaeidae) damage

Field and laboratory studies were conducted to identify potential resistance among crape myrtles, Lagerstroemia spp., to Japanese beetle, Popillia japonica Newman and to flea beetles, Altica spp. Damage ratings revealed variation among cultivars in susceptibility to beetle feeding. Cultivars with Lagerstroemia fauriei Koehne in their parentage exhibited the least amount of damage in choice and no-choice experiments, with few exceptions. The data indicate that both beetle species cause more feeding damage on certain cultivars of Lagerstroemia indica L., such as 'Country Red', 'Twilight', and 'Carolina Beauty' than interspecific cultivars with L. fauriei in their parentage, such as 'Natchez', 'Tonto', and 'Muskogee'. When comparing the effect of parentage on all of the major pests of crape myrtle, L. faurei confers resistance to all pests except crape myrtle aphid. No correlation was found between leaf toughness, leaf color, and leaf nutrients in estimating flea beetle cultivar preference. With this information, growers can more effectively target scouting measures to the most susceptible cultivars. and breeders can select plants that will require the fewest chemical inputs.     

No-choice preference of cerotoma trifurcata (coleoptera: chrysomelidae) to potential host plants of bean pod mottle virus (Comoviridae) in Iowa

To better understand the naturally occurring host range of Bean pod mottle virus (family Comoviridae, genus Comovirus, BPMV) and its principal vector Cerotoma trifurcata (F?rster) (Coleoptera: Chrysomelidae), 18 field-collected perennial plant species were tested for the presence of BPMV. By using no-choice assays, we determined the preference of these plants by bean leaf beetle, by measuring their level of herbivory relative to soybean, Glycine max (L.). New food hosts for adult bean leaf beetles include Lespedeza capitata (Michaux), Lotus corniculatus L., Trifolium alexandrinum L., Trifolium ambiguum Bieberstein, and Trifolium incarnatum L. Desmodium illinoense Gray is discovered as a new naturally occurring host for BPMV.