Control Of Corn Earworm Research Articles

Insecticide Sprays for Control of Insects on Various Vegetable Crops

The need to increaserates of currently recommended chemical insecticides for control of lepidopterous and aphid pests of various vegetable crops demands continued evaluations of the more recently developed insecticides. These materials can then be recommended for the control of the pest species in the event that the recommended materials fail to control the insect pests species or other restrictions prevent their use. Experiments were therefore conducted during the spring of 1959, fall, winter, and spring of 1962, and fall and winter of 1963, at Weslaco, Progreso, and Crystal City to evaluate insecticides for control of the cabbage looper, Trichoplusia ni (Hiibn.), and the cabbage aphid, Brevicoryne brassicae (L.), on cabbage, and the corn earworm, Heliothis zea (Boddie), on lettuce and sweet corn. Shorey (1963) stated that Bayer 44646, Monsanto 40273, and Zectran effectively controlled the cabbage looper on cabbage. Shorey & Hall (1963) showed that high dosages of Bacillus thuringiensis var. thuringiensis were promising for cabbage looper control. These authors also showed that corn earworm control was obtained with DDT + toxaphene, malathion, and toxaphene on poled tomatoes. Wolfenbarger & Getzin (1962) showed that carbaryl effectively controlled the corn earworm on lettuce and that the parathion + toxaphene combination, endrin, and B. thuringiensis controlled cabbage looper populations on cabbage.

The Effect of Insecticides, Rates, Intervals Between, and Number of Applications and Insecticide-Oil and Surfactant Combinations for Insect Control on Southern peas1

Bidrin® (3-hydroxy- N, N -dimethyl- cis -croton-amide dimethyl phosphate), Monsanto 40294 ( O-p -nitrophenyl 0 -phenyl methylphosphonothioate), Bayer 25141 ( O, O -dieliethyl O-p - (methylsulfinyl) phenyl phosphorothioate), Guthion® ( O, O -elimethyl S- (4-oxo-I,2,3-benzotriazin-3 (4- H )-ylmethyl) phosphorodithioate) and carbaryl were the most effective compounds for control of the cowpea curculio, Chalcodermus aeneus Boheman, on southernpeas. Toxaphene was variable in effectiveness. Bidrin, Monsanto 40294 and Bayer 25141 were the most effective compounds for control of the leafminer Liriomyza munda Frick. No differences were found between 2, 4, and 7 applications of carbaryl for cowpea curculio control. No differences were found between 2 and 7 applications of Guthion for cowpea curculio control. Bidrin increased in control as the number of applications were increased to 7. Seven applications of Bidrin. Guthion, and carbaryl were superior to 1–4 applications for control of the corn earworm, Heliothis zea (Boddie). Four applications of Bidrin increased corn earworm control over 1–3 applications while no significant differences were found between 1–4 applications of Guthion and carbaryl. Oil-toxaphene and -endosulfan combinations varied in effectiveness for cowpea curculio and leafminer control in 2 experiments, Penetrant NS-139 increased the effectiveness of bidrin as a leafminer toxicant and to a lesser degree a toxicant against the cowpea curculio.

On the Control of Corn Earworm, Heliothis zea, and Dusky Sap Beetle, Carpophilus lugubris, in Sweet Corn1

In 1959, 1960, and 1961 several candidate insecticides were tested for control of the corn earworm, Heliothis zea (Boddie). and the dusky sap beetle, Carpophilus lugubris Murray. In 1959 two materials, other than the standard DDT-oil emulsion. showed promise as good insecticides for earworm control. These were Sevin® (1-naphthyl N -methylcarbamate) and Thiodan® (6,7.8,9,10,10-hexachloro-1,5.5a, 6, 9,9a-hexhaydro-6, 9-methano-2,4,3-benzodioxathiepin-3-oxide). Sevin and Thiodan also gave significant Slip beetle control. In 1960, these two insecticides again gave a high degree of control. Several compounds that showed promise in 1959 for sap beetle control were added to DDT-oil emulsion to determine the effectiveness of the combination of materials for earworm and sap beetle control. Effectiveness was not increased by the addition of several phosphorus-containing insecticides to the DDT-oil emulsion spray. In 1961 several phosphorus-containing compounds and carbamates were tested and compared with the DDT-oil emulsion standard treatment. Only Sevin was equal in effectiveness to the standard treatment. Guthion® ( O,O -dimethyl S -(4-oxo-1,2,3, benzotriazin-3(4 H )-ylmethyl) phosphorodithioate) gave significant control of earworll but was /lot so effective as the DDT-oil emulsion or Sevin.

The Effect of Plant Type upon Corn Earworm Control in Sweet Corn 1

During three growing seasons, lines of sweet com varying in plant type characteristics were grown in the presence of high populations of the corn earworm ( Heliothis zea (Boddie)). The accumulated data indicate that there was a significant variation between lines in their ability to resist earworm attack but that plant type did not affect the degree of resistance to earworm attack.

A Comparison of the Toxicity of Insecticides for the Control of Corn Earworm on Sweet Corn1

Experiments to control the corn earworm, Heliothis zea (Boddie), have been conducted in southern California with 69 different formulations during the past 10 years. These individual-ear, paint-brush dust tests showed Sevin® (1-naphthyl- N -methyl carbamate), Thiodan® (6,7,8,9,10, 10-hexachloro-1,5,5a,6,9,9a-hexahydro- 6,9-methano-2,4,3-benzodioxathiepin-3-oxide), heptachlor, Dipterex® ( O, O -dimethyl 2,2,2-trichloro-1-hydroxyethylphosphonate), and isodrin equal to or slightly better than a 5% DDT standard treatment. The higher dosages of malathion, Diazinon® (O,O -diethyl O -(2-isopropyl-4-methyl-6-pyrimidinyl) phosphorothioate) and Guthion® ( O, O -dimethyl S -(4-oxo-3H-l, 2,3-benzotriazine-3-methyl) phosphorodithioate) approached DDT in effectiveness, while all other materials were poor or ineffective.

Factors Affecting the Results of Corn Earworm Control Studies

EVALUATING INJURY: Most workers have estimated the degree of corn earworm injury by two basic methods: 1) the percentage of injured or uninjured ears, and 2) by an injury index to show the average degree of injury per ear. To determine the injury index, numbered categories are arbitrarily based on the depth of injury from the tip of the ear by earworms entering through the silk channel, and on the number of kernels damaged by insects attacking the ear by chewing through the husk. The number of ears in each category is multiplied by the category number. These products are then summed and the total divided by the number of ears examined. Walter (1948) described a method in which the categories are numbered from 0 to 5 with 0 indicating no injury and 5 indicating the greatest amount of injury. He also estimated the average number of kernels that are destroyed for each category of injury. Connell (1956) developed an instrument to facilitate measuring the depth of injury. Ditman and Ditman (1957) described another instrument for this purpose. They also gave details of a method by which the depth of earworm injury can be used to estimate the actual percentage loss of kernels by weight. During the summer of 1956, the author compared the two basic methods of evaluating corn earworm injury in popcorn and field corn variety trials, and in chemical control experiments on sweet corn. The two methods were compared by several statistical measurements: the treatment F value; the coefficient of variation; the lowest significant difference by the Multiple Range Test; and, the percentage that the lowest significant difference was of the average amount of injury in the experiment. A higher treatment F value would imply that a method was more likely to detect significant differences among treatments. The coefficient of variation is the square root of the error means square divided by the average amount of injury for the experiment. The precision of an experiment varies inversely with the size of the coefficient of variation (Snedecor 1946). The lowest significant difference by the Multiple Range Test is that value used to compare two adjacent, ranked means (Duncan 1953). It is analagous to the L.S.D. The Multiple Range Test value cannot be used directly for comparing the two methods as they give injury evaluations that are numerically different from each other. However, by dividing the lowest significant difference by the average amount of injury and multiplying by 100, percentage values for each method are obtained which can be compared. These percentage values merely reflect the coefficient of variation but are given for amplification.

Studies on Corn Earworm Control in the Everglades

The corn earworm, Heliothis zea (Boddie), is the most damaging insect that attacks sweet corn in Florida. This is especially true as most of the corn is sold as fresh corn under the grade of U. S. Fancy. Among other requirements, a U. S. Fancy ear must show no evidence whatever of corn earworm attack to the ear itself or even within the silk channel. No vegetable pest requires a more intensive spray program than that necessary to control this pest. Everglades growers spray or dust at least every other day from the time the first silks appear within a planting, until all the silks are dry. Where large acreages of corn are involved, the same sprayer or duster may be operated 24 hours a day. The author's primary objective in corn earworm control studies on sweet corn is to find ways to reduce the number of necessary insecticide applications, and, at the same time, maintain a high degree of corn earworm control. To date the fulfillment of this objective has not been accomplished. Spray applications were made with a high-clearance, self-propelled sprayer built at the Everglades Experiment Station 2. A Myers jumbo nozzle fitted with a No. 3 disc was used on each side of the sweet corn row. The nozzles were at approximately the same height as the silks, and at a right angle to the stalks. The spraying pressure was 200 pounds per square inch. For all trials, Golden Security variety of sweet corn was planted in rows that were three feet apart and thinned to give a 12-inch spacing within the row. Budworm and disease control was accomplished with DDTparzate sprays until the time of silking. Experimental insecticide applications were begun the day after the first silks appeared and continued until all silks were dry. In each experiment a randomized complete block design employing four replications was used. A 100-ear sample was examined in each plot to determine the percentage of ears that were free of earworm injury. Before analysis of variance was conducted, these percentages were transformed to angles (arc sin V % ).

Control of Corn Earworm in Sorghum Heads by Aerial Spraying in Southwestern Kansas1

Journal Article Control of Corn Earworm in Sorghum Heads by Aerial Spraying in Southwestern Kansas Get access Lester J. Depew Lester J. Depew Kansas Branch Agricultural Experiment Station, Garden City Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Economic Entomology, Volume 50, Issue 2, 1 April 1957, Pages 224–225, https://doi.org/10.1093/jee/50.2.224a Published: 01 April 1957

Experiments with Some Mosquito Repellents for Corn Earworm Control on Sweet Corn

Insect repellents have been more generally used against the insects that attack man than for the protection of agricultural crops. In spite of the wide popularity and high effectiveness of the hydrocarbon and phosphatic insecticides, the idea of protecting a crop by preventing insect oviposition or feeding is fascinating. This is particularly true of an insect such as the corn earworm, Heliothis armigera Hbn., which has a high biotic potential, a wide range of host plants and which is, under some conditions, difficult to control with insecticides. DDT-either in a dust or a liquid form-is highly effective against the corn earworm on sweet corn when populations of this insect are low to moderate in numbers. But during periods when populations of earworms are high, adequate control is difficult to obtain. Oil-DDT mixtures applied at 48-hour intervals give the highest degree of control; however, under some conditions such applications may reduce the yield of marketable sweet corn. The cost of such frequent applications is an additional stimulant to the investigation of the effectiveness of repellents. Dethier (1947), in his discussion of repellents, has pointed out that the investigation of repellents has been largely by the hit-or-miss trial method. This method has been used of necessity because there appears to be no relationship between repellency and chemical structure. Our knowledge of the mode of action of repellents is, thus far, limited to the simple fact that some chemicals repel insects and others do not. Lime and Bordeaux mixture were among the first materials used for their repelling effect. These two materials have been shown to repel a number of insects, including flea beetles, leafhoppers and cucumber beetles. Plant extracts have been found to repel some insects. Derris repels the Japanese beetle (Fleming and Baker 1936), rotenone extracts and rotenone-bearing dusts alone or in combination with Bordeaux Mixture repels the Mexican bean beetle (Huckett 1941) and the Colorado potato beetle (Turner 1932). Nicotine sulfate in combination with

The Effect of Particle Size of the Active Ingredient in DDT Dust on Corn Earworm Control

DDT, in dust formulations or as an emulsifiable concentrate alone and combined with mineral oil, has become the standard insecticide against the corn earworm, Heliothis armigera (Hbn.), on sweet corn. The fresh corn market demands a fancy, undipped, worm-free product. In areas where sweet corn is grown principally for the fresh market and where earworm populations are usually very high during the latter part of the growing season, DDT has not been entirely satisfactory as a control measure, either in dust or liquid form.

Control of Corn Earworm and Stored Grain Insects in Single-Cross Corn

Control of Corn Earworm and Stored Grain Insects in Single-Cross Corn

Corn Earworm Control with Airplane Applications of 10 Percent DDT Dust

Corn Earworm Control with Airplane Applications of 10 Percent DDT Dust

Control of Corn Earworm and Rice Weevil in Dent Corn with DDT- Mineral Oil Emulsions

Control of Corn Earworm and Rice Weevil in Dent Corn with DDT- Mineral Oil Emulsions

Control of Corn Earworm Attacking Sweet Corn in California1

Control of Corn Earworm Attacking Sweet Corn in California1

Corn Earworm Control: Timing and Number of Applications

Corn Earworm Control: Timing and Number of Applications

Control of Corn Earworm in Sweet Corn in Alabama

Journal Article Control of Corn Earworm in Sweet Corn in Alabama Get access W. G. Eden W. G. Eden Alabama Polytechnic Institute, Auburn Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Economic Entomology, Volume 45, Issue 1, 1 February 1952, Pages 105–108, https://doi.org/10.1093/jee/45.1.105 Published: 01 February 1952

Studies on Control of Corn Earworm on Sweet Corn in Southern California in 194912

Journal Article Studies on Control of Corn Earworm on Sweet Corn in Southern California in 1949 Get access L. D. Anderson, L. D. Anderson University of California Citrus Experiment Station, Riverside Search for other works by this author on: Oxford Academic PubMed Google Scholar H. T. Reynolds, H. T. Reynolds University of California Citrus Experiment Station, Riverside Search for other works by this author on: Oxford Academic PubMed Google Scholar J. W. Hashe, J. W. Hashe University of California Citrus Experiment Station, Riverside Search for other works by this author on: Oxford Academic PubMed Google Scholar J. E. Swift J. E. Swift University of California Citrus Experiment Station, Riverside Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Economic Entomology, Volume 44, Issue 6, 1 December 1951, Pages 905–909, https://doi.org/10.1093/jee/44.6.905 Published: 01 December 1951

Investigations of Corn Earworm Control on Sweet Corn in California in 195012

Investigations of Corn Earworm Control on Sweet Corn in California in 195012

Corn Earworm Control Experiments in Pennsylvania in 19501

Corn Earworm Control Experiments in Pennsylvania in 19501

DDT-Oil Emulsion for Combined Control of Corn Earworm and European Corn Borer

DDT-Oil Emulsion for Combined Control of Corn Earworm and European Corn Borer