Evaluation of strawberry sap beetle (Coleoptera: Nitidulidae) use of habitats surrounding strawberry plantings as food resources and overwintering sites

The matrix of strawberry and alternate host crops, wooded areas, and uncultivated sections that comprises a farm landscape provides not only food resources but also habitat in both a spatial and temporal context. Reports of the strawberry sap beetle as a pest in strawberry in the northeastern United States have increased along with a trend to produce a wider diversity of fruit crops on individual farms. The three objectives of this study focused on determining which, if any, habitats outside strawberry plantings are important to consider when developing control strategies for strawberry sap beetles. First, sampling of wooded areas and multiple crops showed that strawberry sap beetles overwinter not only in wooded areas but also in blueberry and raspberry. No overwintering beetles were found in strawberry. Second, up to a 70-fold increase in mean number of strawberry sap beetles in a no-choice food source experiment indicated that considerable reproduction can occur on blueberry, cherry, raspberry, and strawberry. Third, sampling summer-bearing raspberry, peach, blueberry, and cherry in 2004 and 2005 confirmed that beetles were present, often in high densities (0.1-108.5 strawberry sap beetles/m(2)), in commercial fields with fruit or vegetable material on the ground. In summary, the beetles are able to feed, complete development, and overwinter in habitats other than strawberry. An effective integrated pest management program to control strawberry sap beetles will need to consider the type of habitat surrounding strawberry fields.     

Suitability of commercially available insect traps and pheromones for monitoring dusky sap beetles (Coleoptera: Nitidulidae) and related insects in Bt sweet corn

Two trap types and pheromone sources for the dusky sap beetle, Carpophilus lugubris Murray (Coleoptera: Nitidulidae), were compared in Bacillus thuringiensis (Bt) and non-Bt sweet corn fields over a 3-yr period. Overall, commercial traps and pheromones were equally effective as experimental traps and pheromones used previously for capturing C. lugubris and other sap beetle species. The commercial trap often caught significantly more Glischrochilus quadrisignatus Say than the experimental trap that had been used in previous studies. Bt corn significantly reduced caterpillar damage to ears compared with the non-Bt isoline and did not adversely affect levels of Orius sp., the most common insect predator. Sap beetle damage was the most common insect damage to Bt sweet corn ears. Sap beetles were detected by traps at population levels below that which are likely to cause economic concern, indicating commercially available traps and pheromone lures for monitoring sap beetles should be suitable for detecting them under commercial growing conditions.     

Multiacreage evaluation of aerially applied adherent malathion granules for selective insect control and indirect reduction of mycotoxigenic fungi in specialty corn

Aerially applied adherent corn flour granules containing 1% malathion were more often as, or more, effective than 15% chlorpyrifos (Lorsban 15G) granules in controlling caterpillars and sap beetles in high amylose corn in 1997 than 1996. Use of malathion granules corresponding closely in size to chlorpyrifos granules in the second year of the study apparently increased relative efficacy. Significantly less corn borer damage occurred on plants (1996) or ears (1997) within 2 wk of application for both types of insecticide granules compared with untreated plots. In 1997, there were sixfold fewer milk stage ears with more than 20 kernels damaged per ear in the malathion-treated plots compared with chlorpyrifos-treated plots, and severity of caterpillar damage was also less in malathion versus chlorpyrifos-treated plots at harvest. Control of beetles (corn rootworm adults and sap beetles) for both treatments was less effective compared with caterpillars. Significant corn rootworm adult control was noted for both chlorpyrifos and malathion in 1996 and significant sap beetle control was noted for the malathion granules in 1997. Significantly fewer live lady beetles, and more dead lady beetles were present in chlorpyrifos-treated plots compared with malathion-treated or untreated plots in 1996. The incidence and severity of Fusarium mold on ears at harvest was often indirectly reduced by both malathion treatments and chlorpyrifos treatments, with the malathion treatment significantly better than the chlorpyrifos treatment in one case.     

Dusky sap beetles (Coleoptera: Nitidulidae) and other kernel damaging insects in Bt and non-Bt sweet corn in Illinois

Bt and non-Bt sweet corn hybrids (Rogers 'Empire' Bt and non-Bt, respectively) were compared for distribution of kernel damaging insect pests in central Illinois in 1998 and 1999. The occurrence and damage by caterpillars [primarily Helicoverpa zea (Boddie)] were reduced by at least 80% in each year for the Bt compared with the non-Bt hybrid. However, the incidence of sap beetle adults (primarily Carpophilus lugubris Murray) was higher, and larvae, lower for the Bt versus non-Bt in 1999. The incidence of ears with more than five kernels damaged by sap beetles was higher for the Bt compared with non-Bt hybrid in 1998 (13.8 versus 5.5%), but nearly equivalent in 1999 (15.3 versus 15.1%, respectively). Distribution of predators on plants (primarily Coccinelidae) and harvested ears (primarily Orius spp.) were not significantly different on Bt versus non-Bt hybrids. Ears with husks flush with the ear tip or with ear tips exposed had significantly higher sap beetle damage for both hybrids, and the Bt hybrids had significantly higher incidence of exposed ear tips in both years. Sap beetle numbers determined by scouting were often proportional to numbers of beetles captured in baited traps, increasing and decreasing at about the same time. However, values determined with traps were typically less variable than when scouted, and time of sampling was typically four times more rapid for each trap than for each 10 plant scout sample when measured in 1999.     

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.     

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.     

SPLAT-OrB reveals competitive attraction as a mechanism of mating disruption in oriental beetle (Coleoptera: Scarabaeidae)

This study compared the efficacy of SPLAT-OrB, a new pheromone formulation for oriental beetle mating disruption that can be mechanically applied, with hand-applied plastic dispensers in commercial blueberry fields. Both formulations were tested at 2.5 and 5 g of the major sex pheromone component (Z)-7-tetradecen-2-one per hectare, and evaluated by measuring trap shut-down, mating success of caged females, and the number of grubs in sentinel blueberry pots baited with tethered females. All pheromone-treated plots had fewer male captures in traps and lower mating success of caged females compared with untreated plots. SPLAT-OrB, and plastic dispensers at the higher rate, also reduced the number of grubs in sentinel pots. To understand the mechanism of mating disruption in oriental beetle, males were observed approaching the pheromone sources in disrupted plots. In addition, male oriental beetle captures were quantified in plots treated with varying SPLAT-OrB dollop densities per ha. Consistent with predictions for competitive attraction, field observations revealed males approaching the pheromone source and male captures decreasing concavely with increasing dollop density. In a mark-release-recapture study, male oriental beetles responded to SPLAT-OrB dollops and plastic dispensers at least 60 m from the source. Additionally, SPLAT-OrB emitted pheromone that was attractive to male oriental beetles for >5 wk; however, emission rates and attraction dropped rapidly during the first 3-4 wk. This study demonstrates the feasibility of using SPLAT-OrB for oriental beetle mating disruption as an alternative to hand-applied plastic dispensers, and conclusively reveals that a principal mechanism is the competitive attraction of males.     

Phenology of Carpophilus spp. (Coleoptera: Nitidulidae) in Stone Fruit Orchards as Determined by Pheromone Trapping: Implications for Prediction of Crop Damage

Traps baited with synthetic aggregation pheromone and fermenting bread dough were used to monitor seasonal incidence and abundance of the ripening fruit pests, Carpophilus hemipterus (L.), C. mutilatus Erichson and C. davidsoni Dobson in stone fruit orchards in the Leeton district of southern New South Wales during five seasons (1991–96). Adult beetles were trapped from September-May, but abundance varied considerably between years with the amount of rainfall in December-January having a major influence on population size and damage potential during the canning peach harvest (late February-March). Below average rainfall in December-January was associated with mean trap catches of<10 beetles/trap/week in low dose pheromone traps during the harvest period in 1991/92 and 1993/94 and no reported damage to ripening fruit. Rainfall in December-January 1992/93 was more than double the average and mean trap catches ranged from 8–27 beetles/week during the harvest period with substantial damage to the peach crop. December-January rainfall was also above average in 1994/95 and 1995/96 and means of 50–300 beetles/trap/week were recorded in high dose pheromone traps during harvest periods. Carpophilus spp. caused economic damage to peach crops in both seasons. These data indicate that it may be possible to predict the likelihood of Carpophilus beetle damage to ripening stone fruit in inland areas of southern Australia, by routine pheromone-based monitoring of beetle populations and summer temperatures and rainfall.     

Relationships between the occurrence of misshapen fruit on late-season strawberry in the United Kingdom and infestation by insects, particularly the European tarnished plant bug, Lygus rugulipennis

In experiments in which the European tarnished plant bug, Lygus rugulipennis, was caged on the developing flowers or young fruits of strawberry, the insects caused malformation of the fruits. Another species of capsid, Plagiognathus chrysanthemi, caused similar damage; this species is less numerous than L. rugulipennis on late-season crops of strawberry in UK. Other insects which sometimes occur in large numbers in the flowers of late-season strawberry, i.e. various species of thrips and pollen beetles, did not cause fruit malformation in caging experiments, though thrips sometimes caused discoloration of the fruit. In field experiments where numbers of L. rugulipennis were reduced by the use of insecticides, the amount of misshapen fruit was reduced greatly compared to untreated plots. Correlations between the numbers of L. rugulipennis present at the early stages of fruit development and damage scores for fruit deformity were highly significant. This capsid is likely to be the major cause of fruit malformation in late-season crops of strawberry in the UK.     

Comparison of economic and plant phenology-based thresholds for management of Lygus lineolaris (Hemiptera: Miridae) in Minnesota strawberries

Field studies were conducted in southeastern Minnesota, 2000-2002, to assess damage potential and management options for adult Lygus lineolaris (Palisot de Beauvois) in June-bearing strawberries (Fragaria x ananassa). The first study was designed to assess the efficacy of a published economic threshold for L. lineolaris nymphs compared with a plant phenology-based threshold management program, targeted at L. lineolaris adults. L. lineolaris nymphs were sampled using the standard white pan beat method; adults were sampled using yellow sticky traps. In the second study, during 2001-2002, caged strawberries were artificially infested with adult L. lineolaris at specific plant growth stages (i.e., vegetative, green bud, white bud, first blossom, peak blossom, first green fruit, and first ripe fruit) to determine the most susceptible growth stages of strawberry. The phenology-based thresholds proved to be more effective in managing L. lineolaris than the current economic threshold based on nymphs. Results from the infestation timing study indicate that early-growth stages (i.e., green and white bud) are most susceptible to adult L. lineolaris feeding damage. During the early-growth stages, only L. lineolaris adults were present; infestations of nymphs occurred primarily from first blossom to green berry. Results from both studies indicate that (1) management of adult L. lineolaris during the early strawberry growth stages is recommended for maximizing marketable yield and (2) the use of plant phenology-based thresholds, when adults are present, will significantly improve insecticide spray timing, and thus minimize the number of insecticide sprays.     

Japanese beetle lures used alone or combined with structurally related chemicals to trap NE China scarabs (Coleoptera: Scarabaeidae)

Scarab beetles are agriculturally important worldwide, and as adults or larvae they may cause damage to the leaves, flowers, fruit, and roots of crops. Previous international studies showed that Japanese beetle (Popillia japonica, Newman) lures, and structurally related chemicals, can attract numerous scarabs. Based on those studies, season-long trials in grape, cabbage, corn and soybean fields were conducted in 2012–2013 in NE China. Tests determined the attractiveness of the Japanese beetle floral lure (phenethyl propionate:eugenol:geraniol, 3:7:3) and sex attractant (Japonilure), alone, combined, or in a mixture with either (Z)-3-hexen-1-ol, anethole = 1-methoxy-4-propenyl benzene or benzyl alcohol, to local Coleoptera. Furthermore, control efficacies based on leaf, ear, and silk damage, as well as reductions of adults on plants, and overwintering larvae, were also determined. Eleven scarab species, and four non-scarab species, were captured. The addition of other chemicals increased the attractiveness of the two Japanese beetle lures to scarabs such as Potosia brevitarsis (Lewis), Oxycetonia jecunda Faldermann, Holotrichia diomphalia Bates et al., Popillia quadriguttata (Fabricius), Maladera verticalis (Fairmaire), and Metabolus impressifrons Fairmaire, and the chrysomelid beetle Chrysomela populi L. The floral lure, and floral lure plus Japonilure baited traps resulted in > 80% overwintering larvae and adult reductions in corn and cabbage fields, whereas the Japonilure traps gave similar results in the soybean fields. This indicates that the commercial Japanese beetle lure combination can be recommended for use by the Chinese farmers in the corn or soybean fields, and that the related chemicals can be used to increase the attractiveness of the Japanese beetle lures.     

Electrophysiological and behavioral identification of a volatile blend involved in host location of female strawberry sap beetle,Stelidota geminata

The strawberry sap beetle (SSB), Stelidota geminata (Say) (Coleoptera: Nitidulidae), is a serious direct pest of strawberries in the northeastern USA. To date, however, no food or pheromone‐based attractants for SSB have been identified. A combination of solid‐phase microextraction, adsorbent sampling, gas chromatography coupled with electroantennographic detection (GC–EAD), and gas chromatography–mass spectrometry was used to identify volatile compounds from strawberry fruit acting as behavioral attractants for female SSB. Consistent EAD activity was obtained for 16 ester compounds. In Y‐tube olfactometer bioassays, the blend of these 16 compounds mixed at a ratio observed from strawberry headspace was significantly more attractive to adult female SSB than a control. Female SSB showed no difference in response levels between the 16‐component blend and a strawberry volatile adsorbent extract. Our data indicate that the combination of the ethyl acetate with some or all of the remaining 15 compounds is necessary for this ester blend to be attractive to female SSB. Previously identified host volatiles found for other species of sap beetles included mostly alcohols associated with over‐ripe fruit rather than the esters identified from ripe strawberries for SSB. A highly attractive synthetic food odor will be useful for developing new management options for SSB.     

Autodissemination of Beauveria bassiana by Sap Beetles (Coleoptera: Nitidulidae) to Overwintering Sites

An autoinoculative device was used to test the ability of sap beetles (Coleoptera: Nitidulidae) to carry a specific strain of Beauveria bassiana (Balsamo) Vuillemin to overwintering sites in a multiyear field study. The device was baited with the pheromone and coattractants for the dusky sap beetle (Carpophilus lugubris Murray) and placed in the field in the fall of each year. The introduced strain occurred at high frequency among the B. bassiana isolated in the fall of all four years tested (100% of all isolates from 21 of 22 collection dates). The introduced strain of B. bassiana was isolated at high frequency from all the B. bassiana-contaminated sap beetles recovered from the overwintering traps (100% of all isolates from 13 of 23 trap/beetle species combinations) and was highest after the longest fall exposure. The introduced strain was primarily isolated from C. lugubris and C. antiquus, but species distribution was also dependent on the overwintering trap design used. Few non-sap beetles species of insects were recovered from the artificial overwintering sites. Although B. bassiana was isolated from free flying sap beetles caught in traps in the spring of each year, none were infected with the introduced strain. The autoinoculating device provides selective contamination of sap beetles in overwintering sites when used in the fall. It may be useful in providing some control of sap beetles or other insects where limited numbers of mass overwintering sites (such as tree holes) occur.     

Distribution, Ecology and Population Dynamics of the American Burying Beetle [Nicrophorus Americanus Olivier (Coleoptera, Silphidae)] in South-central Nebraska, USA

The endangered American burying beetle, Nicrophorus americanus Olivier, was previously widespread throughout eastern North America. In the past century numbers of this beetle have drastically declined and currently remnant populations are known from only six states despite intensive surveying efforts conducted for the last nine years. Efforts aimed at discovering and managing remnant populations have been generally limited by a lack of knowledge concerning N. americanus biology. We used baited pitfall traps to define the range of the Gothenburg, Nebraska population of N. americanus. Using mark-recapture techniques, we estimate that the annual Gothenburg population consists of more than one thousand individuals, meeting the recovery plan criterion to become the third breeding population in the Midwest region. Beyond estimates of population size and range, we present novel data on seasonal and daily activity, sex ratio, age-grading and foraging distances. In 1995 and 1996, the Nebraska population was univoltine and female biased, with over-wintering mature beetles emerging in early June and teneral beetles emerging in August. Nocturnal activity was highest in the third and fourth hours following sunset but was not strongly correlated with temperature. During foraging, beetles travel up to six kilometers, but the majority of our recaptures occurred at distances of less than 0.5 km, suggesting that distances between traps be increased to ensure independence of sampling units. This information will allow future work on captive breeding, re-introduction and genetic studies.     

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.     

Ecological methods for adult populations of Oryctes rhinoceros (Coleoptera, Scarabaeidae)

ABSTRACT. 1. For comparing assessment methods, O.rhinoceros (L.) populations were monitored in five 30–50 ha plots in southern Luzon, Philippines. No consistent correlations were found between number of beetles caught in traps, amount of palm damage and number of breeding sites. Apparently, plots were too small to account for fast dispersal of beetles.
2. Coconut cap traps baited with ethylchrysanthemumate attracted O.rhinoceros adults searching for breeding sites. Several factors were identified influencing catches but trapping was found to be unsuitable for accurately assessing pest populations.
3. A new method which gives estimates on the monthly number of O.rhinoceros attacks on coconut palms, was tested in the Maldives. Palms are climbed about once a year and the sequence of fronds, the number and the position of beetle cuts are recorded.
4. Reduction with age of the length of three teeth on the fore tibia of O. rhinoceros adults was studied in the Philippines. The data was insufficient to obtain a clear correlation between age and length of teeth.
5. The observations indicated that in the Philippines after leaving their site of pupation, O.rhinoceros adults spend about 5 weeks feeding on coconut palms. This is followed by a period of about 7 weeks in breeding sites and, on occasion, additional visits to palms. With these estimates it was possible to relate palm damage records with numbers of feeding adults.     

Agricultural Land Use Determines the Trait Composition of Ground Beetle Communities

In order to improve biological control of agricultural pests, it is fundamental to understand which factors influence the composition of natural enemies in agricultural landscapes. In this study, we aimed to understand how agricultural land use affects a number of different traits in ground beetle communities to better predict potential consequences of land-use change for ecosystem functioning. We studied ground beetles in fields with different agricultural land use ranging from frequently managed sugar beet fields, winter wheat fields to less intensively managed grasslands. The ground beetles were collected in emergence tents that catch individuals overwintering locally in different life stages and with pitfall traps that catch individuals that could have a local origin or may have dispersed into the field. Community weighted mean values for ground beetle traits such as body size, flight ability and feeding preference were estimated for each land-use type and sampling method. In fields with high land-use intensity the average body length of emerging ground beetle communities was lower than in the grasslands while the average body length of actively moving communities did not differ between the land-use types. The proportion of ground beetles with good flight ability or a carnivorous diet was higher in the crop fields as compared to the grasslands. Our study highlights that increasing management intensity reduces the average body size of emerging ground beetles and the proportion of mixed feeders. Our results also suggest that the dispersal ability of ground beetles enables them to compensate for local management intensities.     

Comparison of naturally and synthetically baited spruce beetle trapping systems in the central Rocky Mountains

We compared naturally baited trapping systems to synthetically baited funnel traps and fallen trap trees for suppressing preoutbreak spruce beetle, Dendroctonus rufipennis Kirby, populations. Lures for the traps were fresh spruce (Picea spp.) bolts or bark sections, augmented by adding female spruce beetles to create secondary attraction. In 2003, we compared a naturally baited system ("bolt trap") with fallen trap trees and with synthetically baited funnel traps. Trap performance was evaluated by comparing total beetle captures and spillover of attacks into nearby host trees. Overall, the trap systems did not significantly differ in spruce beetle captures, although bolt traps caught 6 to 7 times more beetles than funnel traps during the first 4 wk of testing. Funnel traps with synthetic lures had significantly more spillover than either trap trees or bolt traps. The study was repeated in 2004 with modifications including an enhanced blend synthetic lure. Again, trap captures were generally similar among naturally and synthetically baited traps, but naturally baited traps had significantly less spillover. Although relatively labor-intensive, the bolt trap could be used to suppress preoutbreak beetle populations, especially when spillover is undesirable. Our work provides additional avenues for management of spruce beetles and suggests that currently used synthetic lures can be improved.     

Efficiency of flight interception traps for adult Colorado potato beetles (Coleoptera: Chrysomelidae)

Interception traps have been used to monitor and sample Colorado potato beetle, Leptinotarsa decemlineata (Say), populations in flight, but the efficiency of these traps was unknown. The efficiency of interception window traps is limited because flying adults avoid the traps and may bounce off the trap without being collected. All trap types tested were avoided in flight chamber tests, including those constructed of transparent Plexiglas or yellow wood boards. A larger screen trap and a harp trap designed to reduce detection were also avoided by the beetles in flight. None of the traps provide a direct estimate of the number of adults randomly flying in the trap area. The highest level of efficiency for window traps was obtained with the yellow trap, which caught 16% of the expected flying population. Harp and screen traps without frames intercepted 60-62% of the expected flying population. The presence of a frame did not increase significantly the avoidance of the screen and harp traps by beetles in flight. Recommendations are made to maintain or increase the efficiency of some traps.     

Alternative management tactics for control of Phyllotreta cruciferae and Phyllotreta striolata (Coleoptera: Chrysomelidae) on Brassica rapa in Massachusetts

The flea beetles Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (F.) (Coleoptera: Chrysomelidae: Alticinae) are significant pests of crops in the Brassicaceae family. From 2001 to 2003, the efficacy of both new and commonly used treatments for the control of flea beetles in brassicas, Brassica rapa L., were evaluated in three small plot, randomized complete block design trials. Row cover and carbaryl (applied as a weekly foliar spray) were found to be the most consistent at reducing damage in comparison with untreated controls in all trials. Two new products that may provide adequate flea beetle control are spinosad (in either conventional or organic formulations) and thiamethoxam. The plant-derived compounds azidiractin and pyrethrin did not protect treated plants from flea beetle feeding. Treatment of plants with kaolin, or removal of the beetles with a vacuum, also did not reduce the level of crop damage. The level of damage at harvest was found to be correlated with population size of flea beetles in each plot, as measured by captures on yellow sticky traps and direct visual counts. Removal of the outer two leaves of individual B. rapa plants reduced the total number of holes per plant by 40%, while only removing 15% of the leaf area.