Flea Beetle Populations Research Articles

Yield Response and Efficacy of Penncap-M on Chinese Broccoli, 1984

Abstract Broccoli yield, population estimates and feeding damage of cruciferous pests were used as indicators to determine the efficacy of Penncap-M. There was a 3-ft row spacing, 1.5 ft between plants, and 3 ft alley spacing between replicates. Treatments were arranged in a randomized block design with 4 replicates. Seedlings were transplanted on 31 Jul, following incorporation of 3 lb 10-10-10 fertilizer/100 sq ft and 10 lb lime/100 sq ft into a tilled plot and fumigation with bromomethane (1 lb/100 sq ft). A compressed air sprayer, with Teejet 8003 Fan type nozzles (one for the first application and 2, with a boom spacing of 30 inches, for the second and third applications) were used to deliver a foliar broadcast spray. Applications were made on 8, 15 Aug, and 5 Sep, coinciding with the seedling, post-seedling and mature plant growth stages. On 2 Aug it was necessary to treat all plants with Lannate to reduce a flea beetle population which would have caused high seedling mortality if left uncontrolled. Yield data were collected on 20 Sep bv weighing whole plants. Adult flea beetle populations on whole plants were assessed on 15 Aug by using the following rating index: 0 = 0 beetles, 1 = 1-10 beetles, 2 = 11-20 beetles, 3 = 21-30 beetles, 4 = 31-40 beetles, 5 = 41-50 beetles, 6 = 50+ beetles. Flea beetle feeding damage was also evaluated on 8 Aug by counting the number of feeding scars in a 1 cm2 area at the center of 1 randomly chosen leaf per plant. At the time of harvest (20 Sep) all imported cabbageworm and cabbage looper larvae on 5 randomly chosen plants per replicate were counted.

Systemic Insecticides on Flue-Cured Tobacco, 1982

Abstract Flue-cured tobacco was transplanted in plots, 40 (24 plants) x 12 ft (3 rows), arranged in a randomized complete block design replicated 4 times on May 19. Spacing was 4 ft between rows and 20 in between plants in the row. The soil was a Chesterfield-Mayodan-Bourne fine sandy loam (pH 5.8, organic matter < 2%). Pretransplant treatments were applied and incorporated on May 17. Liquid formulations were applied with a CO2-powered backpack sprayer operated at 20 psi and delivering 30 gal of finished spray/acre using flat fan (8004) tips. A Gandy 901 applicator, mounted on a pushcart, was used to broadcast granules through a series of 10 in Ro-banders. Broadcast treatments were incorporated with a rotary tiller. In-row applications of Temik were delivered in a 12 in band using a single Ro-bander and followed immediately by bedding. Hand operated dusters were used to make sidedress applications of Di-Syston and Temik in 4 to 6 in bands at 3 (Jun 9) and 5 (Jun 23) wk after transplanting, respectively. The sidedress treatments were immediately incorporated by cultivation. Recommended practices were followed for weed control and fertilization and Ridomil was applied for disease control. Aphid densities were estimated for 2 upper leaves of 10 plants/plot every 1 to 2 wk during Jul and early Aug. On Aug 20, aphid damage was rated on a scale of 0 - 5, where 0 = no damage and 5 = very severe damage. A D-Vac sampler was used to sample flea beetle populations on the center row of each plot on Jun 3; and flea beetle feeding holes were counted on the most damaged leaf of 10 plants/plot on Jun 7. On Jun 28, 3 plants in the outside row of each plot were cut off at 6 in, the remaining leaves removed, loose soil brushed away from the base of the plants, and 20 (diameter) x 24 in (height) emergence cages were placed over the stubs and root systems. Flea beetles were counted and removed from the cages once or twice a week from Jun 30 to Jul 22. Hornworms and the number of leaves destroyed by hornworms were counted on the center row of each plot on Aug 11 and Jul 14, respectively. Tobacco was harvested at the appropriate time, cured and graded. Analysis of variance tests were conducted on the resulting insect counts, yields and values, and Duncan’s multiple range test was used to separate treatment means. Green peach aphid counts were transformed to Log,n prior to analysis.

WINTER SAMPLING TO DETERMINE OVERWINTERING SITES AND ESTIMATE DENSITY OF ADULT FLEA BEETLE PESTS OF RAPE (COLEOPTERA: CHRYSOMELIDAE)

AbstractThe three most important flea beetle pests of western Canadian rape crops appear to be selective in choosing their overwintering sites, as the greatest densities of overwintering adults of Phyllotreta cruciferae (Goeze) and Psylliodes punctulata Melsh. were found in leaf litter and turf beneath hedges and(or) shelterbelts, while that of Phyllotreta striolata (F.) was found in these materials beneath groves of native trees. Most beetles overwintered near the surface in leaf litter and turf rather than in the underlying soil. Within a habitat, sample to sample variation for each species was usually large and the overwintering populations appear to have an aggregated distribution pattern. Winter samples over a 6-year period from all five habitat types combined or from parkland groves reflected the continuously low level of the field population of Psylliodes punctulata, and a marked increase in the field population of P. striolata that occurred in one year. Winter samples taken from hedges and(or) shelterbelts provided little information on population sizes or trends except for indicating the general low level of the Psylliodes punctulata population. Winter mortality was low for all three species. The foregoing information will be useful for developing future sampling plans so that overwintering flea beetle populations can be estimated more reliably.

Evaluation of Insecticides to Control Insects on Flue-Cured Tobacco in Virginia, 1978

Abstract ‘McNair 944’ flue-cured tobacco was planted on May 21 at the Southern Piedmont Research and Continuing Education Center, Blackstone, Virginia. Four-row plots 40 ft long were arranged in a randomized complete block design replicated 3 times. Insecticides were applied to Test 1 on July 5 and to Test 2 on Aug 16 at 23.3 gal/acre using a CO2 powered back-pack sprayer with an operating pressure of 60 psi. A single solid cone nozzle was used to apply insecticides to individual rows. In addition to natural populations of tobacco hornworms, tomato hornworms, tobacco flea beetles, and green peach aphids, plots were artificially infested with three tobacco hornworms and one tobacco budworm per plant 5 days before treatments were applied. Immediately following the completion of the first test, the tobacco was cut back to ca 6 inches and single suckers were allowed to grow from each stub. Tobacco flea beetle and green peach aphid populations were counted on 5 plants per plot. Flea beetles were counted on one side of randomly selected plants, while green peach aphids were counted or estimated on 2 upper leaves of the sample plants. Tobacco hornworms, tomato hornworms, and tobacco budworms were counted on all plants in the 2 center rows of each plot. Aphid counts were transformed to Log (aphid count + 1) before analysis.

Effect of Host-Plant Nutrition on the Occurrence of Tobacco Hornworms and Tobacco Flea Beetles on Different Types of Tobacco12

In a field experiment conducted during 1977, deficient, normal, and excessive levels of nitrogen, phosphorus, and potassium were compared alone and in all possible combinations (27 treatments) to determine their effects on the abundance of the tobacco horn worm, Manduca Sexta (L.), and the tobacco flea beetle, Epitrix hirtipennis , (Melsheimer) on 3 types of tobacco, Nicotiana tabacum L. Although nitrogen had significant effects on tobacco flea beetle abundance during some sampling periods, the effect over the entire season was not significant. Tobacco flea beetle populations decreased significantly as phosphorus was increased from deficient to normal levels and from normal to excessive levels. Low potassium levels resulted in significant reductions in tobacco flea beetle populations. A portion of this reduction was attributed to the smaller size of potassium deficient tobacco plants. Tobacco horn worm populations were highest on tobacco receiving low levels of phosphorus and high levels of nitrogen and potassium. Dark-fired tobacco had significantly fewer tobacco flea beetles and tobacco horn worms than flue-cured and sun-cured tobaccos. Nutritional effects (N, P, and K) appeared to result in independent effects, i.e., there were no significant N-P-K interactions or nutrient X type interactions for the insect population densities observed.

Insect Control on Dark-Fire Tobacco, 1978

Abstract ’Virginia 309’ dark fire-cured tobacco was transplanted on May 25’78 in 4 ft rows with 26 inch spacing. Treatment plots 40 ft long and 4 rows wide were arranged in a randomized complete block design replicated 3 times. Granular insecticides were ap-plied with a hand operated Cyclone narrow band spreader. Furadan 4F was applied with a 2.5 gal CO2~p0wered knapsack sprayer operated at 30 psi and deliv-ering 30 gal of finished spray/acre through a Whirljet nozzle. Preplant soil-incorporated treatments were applied and incorporporated by disking on May 19,78. Plot soil had a fine sandy loam texture and the temperature was ca 80� F at the time of application. Spray treatments were applied on July 11 using a CO2-powered knapsack sprayer operated at 60 psi and delivering 23.3 gal/acre through a single solid cone nozzle. Insect counts and yield data were determined for the 2 center rows of each plot. Green peach aphid counts were made by estimating the number of aphids present on 2 upper leaves of 10 plants/plot and tobacco flea beetle populations were counted for one side of 10 plants in each plot. Tobacco hornworms were counted on all plants in the 2 center rows of each plot.

LABORATORY AND FIELD STUDIES ON THE CHEMICAL CONTROL OF THE CRUCIFER FLEA BEETLE, PHYLLOTRETA CRUCIFERAE (COLEOPTERA: CHRYSOMELIDAE), ON CRUCIFEROUS CROPS IN ONTARIO

AbstractThe crucifer flea beetle, Phyllotreta cruciferae (Goeze), is a pest of major economic importance on cruciferous crops in Canada. Laboratory and field tests were conducted to assess the effectiveness of insecticides which have been, or currently are used in Ontario, or which might have potential for its control. Twenty of 22 insecticides tested in the laboratory were toxic or moderately toxic by direct contact against adults. Carbofuran was 55 times and eight other insecticides 2.9 to 5.5 times more toxic than endosulfan. Of eight insecticides tested as soil treatments, diazinon, carbofuran, and dieldrin were most toxic to adults. All insecticides were less toxic in organic than in mineral soil. In field studies, concentrations of DDT and dieldrin typical of those found in mineral soils used for crucifer production in Ontario in the late 1960’s reduced crucifer flea beetle damage to radishes. As organochlorine insecticide residues decline a higher percentage of crucifer flea beetle population will survive necessitating greater emphasis on control. Two sprays of parathion, carbaryl, or endosulfan significantly reduced crucifer flea beetle damage to radishes in the early part of the growing season under moderate insect pressure. These control programs were less effective during warmer weather and(or) under severe crucifer flea beetle pressure. Soil applications of terbufos, carbofuran, and oxamyl protected cabbage grown in seed beds from attack. The latter was slightly phytotoxic. Planting–water treatments using azinphosmethyl, diazinon, and oxamyl protected cabbage transplants against early season crucifer flea beetle attack. On late cabbage, fensulfothion, azinphosmethyl, carbaryl, endosulfan, and chlorfenvinphos gave good protection.

Greenbug Control on Grain Sorghum and the Effects of Tested Insecticides on Other Insects1

A new biotype of Schizaphis gramimun (Rondani) caused severe and widespread damage to sorghum, Sorghum bicolor (L.) Moench, in the summer of 1968. Screening tests and refinement of application rate studies were conducted in 1968 and 1969 to determine if compounds used in greeubug control on wheat could be used effectively also against this biotype. The most feasible chemicals, considering both insecticidal and nonphytotoxic properties, were disulfoton, parathion, diazinon, demeton, and ULV malathion. Carbophenothion, although somewhat slower acting, was also usually very effective. Supracide® ( S -((2-methoxy-5-oxo-∆2-l,3,4-thiacliazolin-4-yl) methyl) O,O -dimethyl phosphorodithioate), while not very effective in the 1968 studies, significantly reduced greeubug populations in the 1969 tests. Most of the insecticides were found to give reductions also in populations of the corn leaf aphid Rhopalosiphum maidis (Fitch). Fall armyworm, Spodoplera frugiperda (J. E. Smith), and flea beetle population differences following insecticidal treatments were not significant. Of the beneficial insects monitored, the primary species present were the convergent lady beetle, Hippodamia convergens Guerin-Meneville, and various parasitic Hymenoptera. In general the more effective the insecticide in controlling the greenbug, the greater its suppressive effect Avas on beneficial insect populations. However, demeton applied at 0.5 lb active ingredient per acre gave satisfactory greenbug control and spared much of the beneficial insect population.

Observations on the ecology of the cotton flea-beetles in the Sudan Gezira and the effect of sowing date on the level of population in cotton

SummaryA series of experiments was undertaken to examine the relative concentration of cotton flea-beetles (Podagrica puncticollis Weise and P. pallida (Jacoby), Halticinae) within cotton fields in the Sudan Gezira in 1954 and 1955. Assessments were carried out on the flea-beetle populations and on the damage done by them, and evidence is produced to show that the use of a damage assessment in the first three weeks of the life of the cotton plant is more satisfactory in a large-scale experiment than beetle counts. The assessment lasted for between three and four weeks after the emergence of the seedling cotton.It appeared that the beetles tended to leave cotton 19 days after sowing. Damage within the cotton field was at first in accord with the sowing differential, but then shifted against this as the flea-beetles moved on to the later-sown cotton as this became more attractive.The peak population of flea-beetles occurred during the last few days of August and the first few of September when the first-sown cotton was 14–18 days old, and this suffered more damage than the later-sown and less attractive cotton. Differences in the level of attack on the four sowings tended to even out, but did not do so completely as the flea-beetle population was declining.

Species Diversity and Insect Population Outbreaks

Species diversity and complexity of association among species were found essential to the stability and balance of the community system. The community associated with Brassica oleracea L. (Cruciferae) was studied on plants grown in single-species planting and on plants grown in the mixed vegetation of a 15-year fallow field. Approximately 300 species of plants and 3,000 species of heterotrophs existed in the fallow field and these provided species diversity. In 1957, 27 taxa were associated with B. oleracea grown in mixed-species planting and 50 taxa were associated with it in the single-species planting. Three to four times as many parasitic and predaceous taxa were present in the single-species planting. Aphid, flea beetle, and lepidopteran populations reached outbreak levels in the single-species planting, but no such outbreaks occurred in the mixed-species planting. These trends were substantiated in 1958. Thus, it was concluded that species diversity play an important role in preventing population outbreaks. Where possible in cultivation, faunal and floral varieties should be encouraged. The use of specific pesticides and biological control agents to remove pests without sterilization should prove a sound practice.

Control of insects attacking the foliage of potato

The experiments herein reported have been concerned with the effectiveness of DDT, parathion, malathon, DDD, TEPP, chlordane, lindane, methoxychlor, aldrin, dieldrin, EPN, Systox, Pestox 3, toxaphene, Q137, and Dilan when used in combination with a suitable fungicide in the control of insects attacking the Irish Cobbler potato. All treatments were applied to plots 2 rows wide and either 10 or 50 feet long, replicated at least 4 times in randomized blocks. The sprays were applied to the larger plots with tractor-mounted equipment and to the smaller areas with a wheelbarrow type sprayer at the rate of 160 gallons under a pressure of 300 pounds per square inch. The first application was made when the plants were about 4 inches high and others followed at 10-day intervals until the plants were dead. Leafhopper populations were determined by counting the nymphs on 10 leaves selected at random from each plot. Since the nymphs seldom leave the plant, they can be counted readily upon an individual leaf, whereas the adult leafhoppers are very active and move freely from plant to plant. Thus, the nymph count was considered to be the better index of relative populations. Flea beetle populations were not determined by actual count of the insects. The number of adult feeding punctures in a unit area of leaf surface was considered to be a more reliable index to the size of the adult population. A sample of 10 leaflets was selected at random from each plot and the mean number of feeding punctures per leaflet was determined for each treatment. Aphid and whitefly populations were detemfined by counting the insects on 10 leaves selected at random from each plot. Since adult whiteflies move rapidly when disturbed, only the nymphs of this species were counted. The degree of foliage protection was determined by estimating the percentage of dead foliage for each plot on a given date. During the course of these experiments, hopperburn represented the most serious injury to the foliage, but in certain years either early or late blight was a contributing factor.