Colorado Potato Beetle Populations Research Articles

Colorado Potato Beetle (Coleoptera: Chrysomelidae) Population Development and Effects on Yield of Potatoes With and Without Straw Mulch

Colorado potato beetle, Leptinotarsa decemlineata (Say), population trends were monitored in potatoes, Solanum tuberosum L., grown in plots with and without straw mulch during 1988 and 1989 growing seasons in Virginia. An insecticide treatment was incorporated into a factorial experimental design (mulch × insecticide) in 1989 to evaluate effects of mulch on potato yield without Colorado potato beetle defoliation. Numbers of overwintered adult beetles, egg masses, and larvae were significantly lower in plots with mulch compared with those without. Soil temperature and moisture conditions were more favorable for potato plant growth in Virginia under straw mulch than in bare ground (no mulch) plots. Final tuber yields were significantly greater in mulched plots (with and without insecticides) compared with plots without mulch in both years of the study. Application of insecticides in 1989 also resulted in higher yields within each mulch treatment. In plots treated with insecticides, six spray applications were required to control Colorado potato beetle populations above economic thresholds in plots without mulch, compared with two applications in plots with mulch. The feasibility of the use of straw mulch in commercial potato production is discussed.

Influence of Colorado potato beetle sample counts and plant defoliation on potato tuber production

Field experiments were designed to subject Superior potato plants to various levels of defoliation by the Colorado potato beetle (CPB)Leptinotarsa decemlineata (Say), Coleoptera: Chrysomelidae. Defoliation occurred during each of five consecutive plant growth periods and CPB population, plant leaf area, and tuber weight data were recorded for each period. A visual defoliation rating scheme provided an accurate estimate of actual potato plant leaf area of defoliated plants. Data generated from regression analysis demonstrated a significant dependence of leaf area on CPB numbers per plant during some plant growth periods, but numbers of CPB accounted for very little of the total variation in tuber weight. Plant leaf area was the most important independent variable in the tuber weight regression model.

Ovariole number of Italian geographic populations of Colorado Potato Beetle (Leptinotarsa decemlineata Say)

Populations of Colorado Potato Beetle (CPB) have been collected in seven Italian locations. The number of ovarioles per ovary amounted to an average of 32.72±3.71, with a range of 21 to 41. These figures are consistant with the reports for CPB from North Eastern North America. The populations studied did not differ significantly among themselves suggesting that the character “ovariole number” is not sufficient to discriminate among CPB populations collected in different Italian areas.

Use of Beauveria bassiana for Suppression of Colorado Potato Beetle Populations in New York State (Coleoptera: Chrysomelidae)

In a 3-yr study, field plots of Katahdin potatoes in Tully, N.Y., were treated with Beauveria bassiana (Balsamo) Vuillemin at rates of 5 × 1012 and 5 × 1013 colony-forming units/ha for control of Colorado potato beetle ( Leptinotarsa decemlineata (Say)). B. bassiana treatments were compared with a control of water plus surfactant and with insecticide treatments of oxamyl (184 g active ingredient [AI]/ha) in 1983, or fen valerate (18.4 g [AI]/ha) plus piperonyl butoxide (PBO) (73.6 g [AI]/ha) in 1984 and 1985. In 1983, B. bassiana and control treatments were not significantly different regarding larval populations or tuber yield, but few adults emerged from B. bassiana -treated plots. Field-collected third- and fourth-instar larvae developed B. bassiana mycoses (98% of the test population for the high rate of B. bassiana and 64% for the low rate) when held at high humidity conditions (RH > 90%) for 11 d. Because the B. bassiana formulation rapidly lost >90% of the spore viability before applications were initiated, no significant results were observed in 1984. The 1985 B. bassiana formulation maintained spore viability well and produced significant reductions in third- and fourth-instar larval populations (65.8% for high and 39.5% for low B. bassiana treatments). For high and low treatments in 1985, respectively, 28.3% and 20.0% of field-collected third- and fourth-instar larvae that were held at high humidity conditions developed B. bassiana mycoses. Adult emergence studies using field cages indicated no reduction in 1985 adult populations for the low B. bassiana treatment, but a 71.6% reduction in the high B. bassiana plots. Total 1985 marketable tuber yields for fenvalerate + PBO, high B. bassiana , low B. bassiana , and control treatments were, respectively, 28.2, 13.6, 8.2, 3.2 t/ha, and were significantly different for all treatments.

Influence of Conservation Tillage Practices on Populations of Colorado Potato Beetle (Coleoptera: Chrysomelidae) in Rotated and Nonrotated Tomato Fields

Field experiments were conducted in conventional-till (CT) and no-till (NT) tomatoes in both rotated and nonrotated fields to determine effects of different cultural practices on population trends of Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say). CPB were more abundant in CT than in NT plots in both rotated and nonrotated tomato fields. Earlier colonization of overwintered adults in CT plots resulted in higher egg mass densities and subsequent infestation of first-generation larvae and adults. In treatments where fenvalerate was applied to control CPB populations above economic thresholds, four spray applications were required in CT plots, compared with two applications in NT. Tomato fruit yield and soil moisture content were greater in NT than in CT plots in the rotated field.

Control of Colorado Potato Beetles on Potatoes with Foliar Sprays, 1986

Abstract This study was located on the William Rodonis Farm, Litchfield, NH, where a Colorado potato beetle population known to be resistant to several registered insecticides is known to occur. The location had been planted with potatoes in 1985 which insured an adequate population of overwintering adults. ‘Norland’ Irish potato seed pieces were planted in rows spaced 3 ft apart on 25 Apr. Temik 15G was applied in the seed piece furrow at planting time at a rate of 20 lb/acre. Each treatment was replicated 4 times in a randomized block design. Spray applications were begun on 10 Jun when the activity of Temik had subsided and adult beetles were laying eggs, Spray applications were made with a R & D C02 pressurized sprayer at a rate of 35 gal/acre (35 psi) using a hand-held boom with 4 nozzles which covered 2 rows. Applications were repeated on 23 Jun, 3 Jun, 15 Jul, and 24 Jul. Evaluations were made on 26 Jun and 17 Jul by counting the live larvae and adult beetles in each plot (50 ft row) that were visible from above without disturbing the foliage. A damage rating assessment was made on both dates using the M. Semel system of: L = visible feeding but less than 10% of foliage consumed; M = 10-25%; VS = greater than 51% but not totally defoliated; DEF = defoliated.

Foliar Applications of Insecticides for Control of Colorado Potato Beetles on Potatoes, 1984

Abstract Potatoes were planted 10 May ’84 in declo silt loam soil at the Aberdeen Research & Extension Center, Aberdeen, ID. The plots consisted of four 25-ft rows planted 36 inches apart. Thirty treatments were replicated 4 times in a complete randomized block design. Treatments were applied 6 Jul with a hand held, 2-row 4-flat fan nozzle, CO2 pressurized sprayer, calibrated to deliver 13 gal/acre at 30 psi. Canola treatments were applied with a battery powered Micron Corporation HERBI sprayer. Colorado potato beetle populations from each plot were sampled 1 day before and 1, 3, 7 days after spraying by counting live larvae that were visible without disturbing the foliage of the middle 2 rows of each plot.

Foliar Applications of Bacillus Thurengiensis for Control of Colorado Potato Beetles on Potatoes, 1984

Abstract Potatoes were planted 19 May, ’84 in declo silt loam at the Research and Extension Center in Aberdeen, ID. The plots consisted of four 25-ft rows planted 36 inches apart. Six treatments were replicated 4 times in a complete randomized block design. Treatments were applied 13 Jul with a hand held, 2-row 4-flat fan nozzles, CO2 pressurized sprayer, calibrated to deliver 13 gal/acre at 30 psi. Colorado potato beetle populations were sampled at 1 day before and 2, 5, 10 days after spraying by counting live larvae and adults that were visible without disturbing the foliage of the middle 2 rows of each plot.

Colorado Potato Beetle (Coleoptera: Chrysomelidae) Development in Relation to Temperature in Wisconsin

The developmental threshold temperature of the Colorado potato beetle (CPB) was studied in controlled-temperature chambers, and threshold temperatures and heat unit (HU) summations were determined for egg, larval, and pupal stages. x -Intercept estimates of the egg, larval, and pupal stages were 11.7, 11.0, and 12.0°C, respectively. HU accumulations, above 11°C required for development of egg, larval, and pupal stages were 67, 224, and 86, respectively. Developmental threshold temperatures and HU accumulations are discussed in relation to studies with other North American and European CPB populations. Population trends observed in the field were closely correlated with those predicted based on HU summations, thus providing a reliable method of predicting biological events of CPB populations in Wisconsin

Control of Colorado Potato Beetle on Irish Potatoes, 1983

Abstract This study was located on the Robert Wiggin Farm, Stratham, New Hampshire. ‘Katahdin’ Irish potato seed pieces were planted in rows 3 ft apart on 10 Jun. Each plot consisted of two 47-ft rows and each treatment replicated four times in a randomized block design. Spray applications of the three rates of CME 13406 were made on 30 Jun. as soon as adults began laying eggs and again on 8 Jul. All treatments received sprays on 18, 28 Jul., 8 and 19 Aug. Applications were made with a B&G CO2pressurized sprayer at a rate of 36 gal/acre (40 lb/in2 ) using a 5-ft handheld boom with four nozzles which covered two rows at a time. Evaluations of the CME 13406 treatments were made on 18 Jul. by counting the live larvae in each plot (94-ft-row) that were visible from above without disturbing the foliage. All treatments were evaluated on 29 Jul. for both larvae adults per plot. Excessive rainfall during the month of May delayed planting. This was followed by dry weather which resulted in poor plant growth and slow development of a Colorado potato beetle population. No attempt was made to obtain yield data.

Colorado Potato Beetle Control Tests with Carbaryl, Dipel, and Carbaryl-Dipel Combinations, 1979

Abstract Observations from previous field tests suggested that a Sevin - Bacillus thuringiensis mixture may have provided better control of Colorado potato beetle (CPB) than Sevin alone. The test reported here was designed to investigate this combination and was conducted at the North Alabama Horticulture Substation, Cullman. Red LaSoda Irish potatoes were planted 20 Mar 1979 in rows with 44 inch centers. Plots were 4 rows by 10 ft with 4 replications in a randomized complete block design. Treatments were all possible combinations of 5 levels of Dipel and 4 levels of Sevin. Treatments were applied on 18 May using knapsack sprayers. Prespray, 4, and 14 day larval postspray counts were made. Prespray larval counts averaged 10.25 ± 6.0 larvae/plant. Adults were present on plants but contributed less than 2% of the total CPB population.

Foliar Sprays of Synthetic Pyrethroids and Numbered Chemicals for Control of Colorado Potato Beetle, Test 10, 1978

Abstract 'Russet Burbank potatoes were planted on Mar 30 in Rirzville silt loam soil (Mesic Calciorthidic Haploxerolls) at Yakima, WA. A high infestation of the second generation of Colorado potato beetle (CPB) adult and larvae were defoliating the plants by Aug 7, the time of insecticide application. The insecticides were applied as foliar sprays in 40 gal/acre with a 2-row portable boom CO2 hand sprayer. The plots were 2-rows wide (5.6 ft) and 25-ft long and each treatment was replicated 4 times in a randomized complete block design. The number of live adults and larvae per rr/ of potato foliage per plot was counted on Aug 8 and 11 (1 and 4 days after treatment). Also, on Aug 8 the potato foliage between the 2 rows of each plot was separated and the number of dead and live adults and larvae per m* of soil surface plot was counted. Since both dead and live adults and larvae were on the soil and only live adults and larvae were on the plants, the percent mortalities were determined as follows: 1) percent mortality for adults or larvae on the soil based on number dead out of total number dead and live on soil; 2) percent mortality of adults or larvae based on number dead on soil out of total number on plants and soil; 3) percent mortality of CPB population based on number dead adults and larvae on soil out of total numbers of dead adults and larvae on plants and soil. The number of insects and the calculated percent mortality for each plot were subjected to analysis of variance using DMRT.

Colorado Potato Beetle Populations and their Effect on Tomato Yield in Maryland1

Abstract First generation of larvae of the Colorado potato beetle (Leptinotarsa decemlineata (Say)) were primarily responsible for a 67% reduction in yield of tomato (Lycopersicon ‘esculentum Mill.) when their numbers increased from 5 to 10 per plant.