Reduced Plant Damage Research Articles

Evaluation of Insecticides for Control of the Army Cutworm1

Dosage mortality regression analyses were completed for 28 candidate insecticides with 6th-stage larvae of Euxoa auxiliaries (Grote) and their oral toxicities were compared with endrin as the standard. As a group, the pyrethroids were more toxic than the organophosphorus insecticides. Bioethanomethrin and permethrin were more toxic than the endrin standard, whereas cypermethrin and fenvalerate were slightly less toxic. Fenpropanate and FMC 26021 ((5-benzyl-3-furyl) methyl(+)- cis -2,2-dimethyl-3-(2-methyl-I-propenyl) cyclopropanecarboxylate) were 2 times, and chlorpyrifos, methamidophos, endosulfan, BAY 77049( 0,0- diethyl- 0 -(2-quinoxalinyl) phosphorothioate), leptophos, and monocrotophos were 3–4 times less toxic than the standard. The remaining insecticides were 5–30 times less toxic than endrin. In greenhouse tests, permethrin, fenvalerate, cypermethrin, and fenpropanate at 0.14–0.28 kg/ha as sprays to barley plants gave control comparable to endrin at 0.28 kg/ha. However, as soil treatments, the pyrethroids were more effective than endrin at comparable rates of application. Endosulfan, chlorpyrifos, leptophos, and monocrotophos required 0.56 kg/ha to produce control comparable to endrin and, except for endosulfan, these insecticides were less effective as soil treatments. Microplot tests on barley confrrmed the effectiveness of the pyrethroids at 0.14 kg/ha both for control of the army cutworm and for significant reduction in plant damage.

Cabbage Caterpillars: Efficacy of Chlordimeform and Bacillus thuringiensis in Spray Mixtures and Comparative Efficacy of Several Chemical and B. thuringiensis formulations123

At least 1/16 lb/acre each of chlordimeform hydrochloride and Bacillus thuringiensis Berliner in a spray were needed for effective protection to cabbage against the cabbage looper, Trichoplusia ni (Hubner), the imported cabbageworm, Pieris rapae (L.), and the diamondback moth, Plutella xylostella (L.). Emulsifiable concentrate formulations of chlordimeform gave better plant protection and tended to give a greater reduction of the cabbage looper population than did a soluble powder formulation of chlordimeform hydrochloride. The addition of foam to the B. thuringiensis spray did not increase plant protection and injured the foliage. A liquid formulation of B. thuringiensis gave more effective plant protection than a wettable powder formulation even though looper populations were generally higher on plots treated with the liquid formulation. Neither formulation was as effective as Dipel® ( Bacillus thuringiensis var. alesti Berliner) in reducing plant damage. Acephate and Monitor® ( O S dimethyl phosphoramidothioate) provided more effective plant protection than did the other compounds.

Economic impact of air pollution on vegetation in New Jersey and an interpretation of its annual variability

New Jersey sustained a $128,019 loss to agricultural crops and ornamental plantings as a direct result of air pollution damage in 1972. The loss was only 11% of that estimated for the previous year by a similar method. Air pollutant concentrations did not decrease from 1971 to 1972 in the agricultural regions of the state during the growing season. Therefore an explanation for the reduction in plant damage was sought in a consideration of several environmental factors that have been known to increase plant resistance to a given dosage of a pollutant in greenhouse experiments. Primarily, the unusual rainfall pattern in 1972 could have induced a water and/or oxygen stress in the plants in the field that protected them from air pollution injury. Other factors, such as temperature, humidity, nutrition, the presence of disease and the use of systemic fungicides, may also have enhanced plant resistance to air pollutants.

Suppression of Armyworm Damage to No-Tillage Corn with Granular Carbofuran12

The effectiveness of 10% granular carbofuran in reducing damage by Pseudaletia unipuncta (Haworth) to corn planted in May was dependent on the date of treatment and rate of application. Equivalent performance was obtained from placement in the seed furrow or in a 5- to 7-inch band in front of the presswheel. When granular carbofuran was applied at planting on May 4, 2.4 ounces active ingredient (AI) per 1000 linear feet of row was necessary for maximum suppression of severe armyworm damage. However, if treatment was delayed until May 20, 0.6 ounces AI/1000 linear feet of row appeared to be effective. When carbofuran was applied at planting on April 20, placement in seed furrow at 2.4 ounces AI/1000 linear feet of row was necessary for maximum reduction of severe armyworm damage. Band placement was ineffective on this date. A laboratory study indicated that reduction in plant damage observed in the field could not be attributed entirely to contact action of carbofuran, but rather to a combination of contact and systemic activity.