Colorado Potato Beetle Infestation Research Articles

Late to the Party—Transferred Mulch from Green Manures Delays Colorado Potato Beetle Infestation in Regenerative Potato Cropping Systems

The Colorado potato beetle (CPB) is an exceptionally challenging potato pest. Some regenerative farmers have reported that the use of transferred green manure mulch can considerably reduce CBP damage. Previous studies confirm this observation, but mainly with straw mulch, which is rarely used in Central Europe, and not embedded in the new regenerative cropping approach. For this, six trials conducted between 2014 and 2019 were evaluated, comparing CPB infestation in potatoes with and without transferred mulch as well as under a plough as a minimum till regime. In three out of six experiments, compost application was an additional factor. (I) Over all experiments, mulch significantly reduced initial infestation (−24%), egg masses (−27%) and larvae (−75%). Compost and reduced tillage added to these effects; (II) Mulch mainly resulted in delayed CPB infestation; (III) In a particularly warm season, when a second generation of CPB managed to emerge, regulatory effects of the mulch were not sufficient; (IV) Combination of transferred nutrient rich green manure mulch with reduced tillage, compost and other regenerative or agro-ecological techniques is recommended to achieve maximum regulation of CPB.

Effect of Crop Rotation Distance on Populations of Colorado Potato Beetle (Coleoptera: Chrysomelidae): Development of Areawide Colorado Potato Beetle Pest Management Strategies

The Colorado potato beetle, Leptinotarsa decemlineata (Say), overwinters adjacent to field edges and infests nearby fields in the spring, primarily by walking. Crop rotation is known to be an effective cultural control against Colorado potato beetle populations limiting spring infestations. Spatial separation is an important consideration in optimizing the rotational effect because long-distance rotations have been shown to reduce Colorado potato beetle infestations. To determine the effect of long-distance rotations on Colorado potato beetle populations in commercial Wisconsin potato production, a geographic area of >18,200 ha (>45,000) acres in southern Portage County, Wisconsin, was selected as an experimental area for areawide pest management of the Colorado potato beetle. From 1997 to 1999, beetle populations at edges within each potato field in this region were determined by spring and fall field sampling. The rotational distance between current and previous potato fields was measured and analysis was run between the distance and Colorado potato beetle populations. Long-distance rotations of >400 m were an effective cultural control management strategy to limit adult beetle infestations in the spring. This strategy can be optimized when collaborating growers are able to maximize their rotational distances by coordinating their rotational schemes within large areawide, geographic locations. Deploying long-distance rotations within a geographic area over many years would limit Colorado potato beetle populations and could result in a significantly reduced Colorado potato beetle populations entering fields in the spring.

Mixed deployment of Bt-expressing eggplant hybrids as a reliable method to manage resistance to Colorado potato beetle

Eggplant cultivations are severely damaged by Colorado potato beetle (CPB) attacks. Two transgenic eggplant hybrids bearing a mutagenized Bacillus thuringiensis Berl. Cry3B gene were tested to assess their resistance to this insect pest. Field trials were performed at two locations for two consecutive years. Transgenic hybrids were deployed as pure stands (100% transgenic plants) and as mixed plot with 20% of non-toxic wild-type plants. Samples were taken bi-weekly to assess insect abundance; at harvest, total yield was recorded. In both locations, CPB infestation was relevant only in 1 of the 2 years. Field observations confirmed that Bt-expressing eggplant hybrids were able to control insect infestation both as pure stands and as the mixed ones. When insect infestation was massive, transgenic hybrids gave a significantly higher yield than untransformed ones, regardless of their deployment method. Mixed deployment of Bt-expressing eggplants may well be considered as a useful means of CPB control, which could possibly help delaying insect adaptation to cry toxin.

Field Evaluation of Natural, Engineered, and Combined Resistance Mechanisms in Potato for Control of Colorado Potato Beetle

The colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae), is the leading insect pest of potato (Solanum tuberosum L.) in northern latitudes. Host plant resistance has the potential use in an integrated pest management program for control of colorado potato beetle. During the 1998 and 1999 seasons, field studies were conducted to compare natural (leptine glycoalkaloids and glandular trichomes), engineered (Bt-cry3A and Bt-cry5 transgenic potato lines), and combined (Bt-cry5+glandular trichomes) plant resistance mechanisms of potato for control of colorado potato beetle. Nine different potato clones representing five different host plant resistance mechanisms were evaluated under natural colorado potato beetle infestation at the Montcalm Research Farm in Entrican, Michigan. The Bt-cry3A transgenic lines, the high leptine line (USDA8380-1), and the high foliar glycoalkaloid line (ND5873-15) were most effective for controlling defoliation by colorado potato beetle adults and larvae. The Bt-cry5 line (SPc5-G2) was not as effective as the Bt-cry3A transgenic lines ('Russet Burbank Newleaf,' RBN15, and YGc3.1). The glandular trichome (NYL235-4) and Bt-cry5+glandular trichome lines proved to be ineffective. Significant rank correlations for the potato lines between the two years were observed for egg masses, second and third instar, and fourth instar seasonal cumulative mean number of individuals per plant, and defoliation. Egg mass and first instar seasonal cumulative mean number of individuals per plant were not strong indicators of host plant resistance in contrast to second and third instars or adults. Based on these results, the Bt-cry3A transgenic lines, the high leptine line, and the high total glycoalkaloid line are effective host plant resistance mechanisms for control of colorado potato beetle.

Managing Colorado Potato Beetles (Coleoptera: Chrysomelidae) and European Corn Borers (Lepidoptera: Pyralidae) in Potato with Foliar Applications of Bacillus thuringiensis Berliner

Application timing and rate combinations of Bacillus thuringiensis Berliner used for protecting Irish potato, Solanum tuberosum L., from defoliation by the Colorado potato beetle, Leptinotarsa decemlineata (Say), and stem injury by the European corn borer, Ostrinia nubilalis (Hübner), were investigated. Significant reductions in defoliation levels during bloom, populations of first-generation potato beetle adults, and the percentage of stems injured by corn borers at the end of the season in B. thuringiensis-treated potato were considered criteria for a successful management strategy. Although Colorado potato beetle infestations were managed effectively with B. thuringiensis, European corn borer populations were not reduced to a commercially acceptable level. In each of 3 yrs, neither an increase in the number of applications (from 1 to 4) nor an increase in rate (from 0.9 to 3.8 liters/ha) of B. thuringiensis subsp. kurstaki improved the level of corn borer control. In contrast, results indicated that 1 application of B. thuringiensis subsp. tenebrionis, timed when there was >1 large potato beetle larva per stem, using a 4.7 liters/ha rate protected the potato crop during the bloom stage. However, this strategy may not be sufficient to prevent significant levels of defoliation by first-generation potato beetle adults during post-bloom or reduce the size of this population, which will infest next season's crop. For this reason, the B. thuringiensis subsp. tenebrionis timing and rate regimen described above may be most effective in fields where the overwintering potato beetle population is predicted to be low to moderate (e.g., <1 adult per 5 stems), whereas two applications may be most effective in fields where densities are greater.

Evaluating Edovum puttleri Grissell and Podisus maculiventris (Say) for Augmentative Biological Control of Colorado Potato Beetle in Tomatoes

Multiple releases of Edovum puttleri Grissell (Hymenoptera: Eulophidae) and Podisus maculiventris (Say) (Heteroptera: Pentatomidae) resulted in increased parasitism and predation rates of eggs of Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), in small plots of staked tomatoes grown in plastic or hairy vetch mulch. No consistent effect of the mulch on CPB infestations was found over the years of the study. No parasitism by E. puttleri occurred in 1995, while parasitism ranged from 0 to 30.6% per sample date in 1997. P. maculiventris nymphs were found at higher densities in release plots and readily attacked CPB egg masses. Despite the ability of both beneficials to search the structurally complex plant and find the pest, the cost of maintaining release rates that were high enough to achieve significant control of the pest would be prohibitive on a larger scale.

Suppression of Colorado potato beetle infestation by pheromone‐mediated augmentation of the predatory spined soldier bug, Podisus maculiventris (Say) (Heteroptera: Pentatomidae)

Summary1 Hardware and protocols were tested to enable individual growers and insectary operators to mass‐produce predatory spined soldier bugs (SSBs), Podisus maculiventris (Say) (Heteroptera: Pentatomidae: Asopinae), for augmentative biological control. Using pheromone‐based technology, an average of 1775 female SSBs (potentially as many as 1.6 million offspring) were captured each year during 2–3 weeks in early spring.2 Data for the first 2 years of a 3‐year project to use SSB for biological suppression of the Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), verified earlier research showing that augmentation of SSB (∼5 nymphs/plant) can significantly suppress CPB infestations. In the third year, wild SSBs were transferred directly from pheromone traps to mid‐plot nursery cages having a mesh size chosen to retain the adult predators but allow their offspring to escape. Pheromone dispensers were placed peripherally to promote dispersal of young predators and immigration of new wild spined soldier bug adults. Pheromone‐mediated augmentation using porous nursery cages and pheromone dispensers was less labour‐intensive than earlier methods, and resulted in significantly improved potato yield.3 Trapping SSB adults early in the spring protects them from parasitization by tachinid flies and scelionid wasps that use the pheromone to facilitate host‐finding. The compatibility of pheromone‐mediated predator augmentation/conservation with implementation of transgenic plants, imidacloprid insecticide, and other biocontrol methods is discussed.

Site-Specific Integrated Pest Management for High-Value Crops: Impact on Potato Pest Management

Site-specific agriculture optimizes agricultural inputs by varying application rates to match within-field requirements. Two years of trials were conducted in rotated commercial potato fields to compare traditional whole-field integrated pest management with site-specific management for Colorado potato beetle, Leptinotarsa decemlineata (Say), green peach aphid, Myzus persicae (Sulzer), and potato leafllopper, Empoasca fabae (Harris). Additionally, the spatial dynamics of Colorado potato beetle populations subjected to whole-field integrated pest management were studied. Colorado potato beetle infestations mostly remained near field edges throughout the season. Highest densities for each life stage remained near the locations of the initial colonizing adults. Even if management thresholds were as low as the 3rd density decile, between 60 and 95% of the field area could be left untreated when the mean density exceeded the threshold. Site-specific management reduced insecticide inputs for the green peach aphid but not for potato leafhopper. Initial Colorado potato beetle colonization pressure, measured as egg mass density ≈7 d after crop emergence, was a significant covariable in determining season-long insecticide requirements. Analysis of covariance demonstrated that after accounting for this variable, site-specific management significantly reduced insecticide inputs compared with whole-field integrated pest management. Cumulative season-long Colorado potato beetle insecticide savings of 30-40% across a broad range of colonization pressures were observed.

Real-time airborne agricultural monitoring

In 1992 growers of high-value crops in central Wisconsin expressed an interest in using real-time remote sensing data for detecting crop stress. In response to this request, the Space Remote Sensing Center built a system based on work carried out by the USDA, ARS in Weslaco, Texas. This new system included a modification from analog to digital cameras that provided a means of overcoming previous barriers that inhibited real-time information delivery. These barriers include automated band to band registration, data calibration, and automated identification and retrieval of desired data frames. During the 1992 growing season weekly airborne acquisitions were attempted with 24–48-hr information delivery to the growers. Digital images were acquired for high value crops such as potatoes, sweet corn, cranberries, and peas. The system enabled detection of stresses such as freeze damage, irrigation problems, and Colorado potato beetle infestations. Experience gained during 1992 guided modification to the system to prepare for the 1993 growing season. This overall effort is helping prepare the market and technology for a real-time agriculture monitoring satellite.

Influence of Extent and Timing of Colorado Potato Beetle (Coleoptera: Chrysomelidae) Defoliation on Potato Tuber Production in Eastern Virginia

A 2-yr field study was done to evaluate tuber production of ‘Superior’ variety potatoes, Solanum tuberosum L., following various levels of defoliation by the Colorado potato beetle, Leptinotarsa decemlineata (Say). Plants were subjected to defoliation during five consecutive plant growth periods, and tuber weights were measured at the end of each period. Additional plants subjected to defoliation were marked with a visual defoliation rating at the end of each period and maintained free of Colorado potato beetle infestation during subsequent growth periods. Tuber weights of these plants were recorded at the end of growth period five. plants were most sensitive to beetle defoliation during the early stages of plant growth up to 60 d after planting. Tuber yield was least affected by beetle feeding damage during later plant growth stages. Up to 100%defoliation during the last plant growth period (75-89 d after planting) did not result in significant reduction in tuber weights, compared with undefoliated plants. Colorado potato beetle counts indicated that plants could tolerate beetle populations well above published threshold levels without a decrease in tuber production, particularly after initiation of bloom.

Control of Colorado Potato Beetle on Potatoes, 1983

Abstract Two experiments were conducted at Yakima, Washington to evaluate insecticides for control of the Colorado potato beetle (CPB): One against first generation larvae (from the overwintering), and the other against first generation adults. Potatoes were planted on 13 Apr in Ritzville silt loam soil (Mesic Calciorthidic Haploxerolls) pH 6.2 and organic matter 1.6% at Yakima, Washington. The insecticides were applied with a 2-row 4-nozzle portable boom, CO, powered sprayer at 50 psi in 50 gal of water per acre. Each plot was 2 rows (34 inch) wide and 25 ft long. Each treatment was replicated 4 times in a randomized complete block design. There were no untreated check plots. At the time of the first experiment, applied on 9 Jun, the potato plants were infested with 2nd, 3rd and 4th stages of CPB larvae, but few adults. At the time of the second experiment, applied 10 Jul, the plants were infested with newly emerged adults of the 1st generation, but few larvae. The potatos were normally sprinkler irrigated with ca. 0.75 acre inch of water applied at 5 to 7-day intervals, but was not irrigated the first 7 days after treatment. The foliage on the 2-row plots was agitated with the hand to dislodge the insects and the number of dead and live CPB larvae or adults per m2 of soil surface per plot were counted on 10 Jun (24 h posttreatment) first experiment, on 11 Jul second experiment. The % control for each plot was calculated based on the number of dead and live CPB adults or larvae found on the soil surface. The % defoliation was estimated (10 Jun) to determine the severity of CPB infestation in the plots. The number of CPB adults and larvae on the plants in 6-row ft per plot were counted 3 days posttreatment to determine the number of insects surviving the treatment and returning to the plants.

Control of the Colorado potato beetle withBacillus thuringiensis varietyThuringiensis

Field tests were conducted to determine the effectiveness of an experimental preparation ofBacillus thuringiensis var.thuringiensis against Colorado potato beetle infestations on potatoes and tomatoes. Applications were made weekly with a tractor-towed commercial sprayer at the rates of either 473, 946, or 2,838 ml. ofB.t.t. in 378.41 of water per 0.4 hectare. Significant reductions were observed in treated plots of all stages of the beetle. All untreated plants were completely defoliated by the end of the test due to beetle feeding. No significant differences were observed among the different treatment levels.

INSECTICIDES FOR CONTROL OF THE COLORADO POTATO BEETLE (COLEOPTERA: CHRYSOMELIDAE)

AbstractSince 1970 the increasing level of Colorado potato beetle infestation in southwestern Ontario has necessitated foliage sprays or planting treatments with systemic insecticides. Spray tower tests of many insecticides against eggs, larvae, and adults indicated that the best overall materials would be carbofuran, azinphos-methyl, and chlorfenvinphos.At planting time furrow treatments with granular carbofuran, disulfoton, or phorate demonstrated good control of all potato pests until the end of June. After that time only the carbofuran and phorate treatments gave protection against a heavy second generation of potato beetles. Yields were related to the degree of pest control.