Effects of Various Fungicides and Insecticides on Emergence of Three Wheat Cultivars1
- B. Khaleeq and
- A. Klatt2
Treatment of seeds with fungicides, insecticides, or a combination of both has been practiced by seedsmen, scientists, and farmers in order to protect seeds and seedlings from different pests. Treating seeds with recommended rates of application is usually safe, but workmen sometimes add more than the recommended rate. Treated seeds are also kept in storage for some time before planting. The purpose of the study was to find out the effects of those chemicals and to determine whether the treated seeds could be stored without loss of viability. Seeds of three wheat (Triticum aestivum L.) cultivars, Bolal, Bezostaya, and Köse 220/39, were treated with the fungicides carboxin [5,6-dihydro-2-methy1-1,4-oxathiin-3-carboxanilide] and benlate [methyl l-(butylcarbamoyl)-2-benzimidazolecarbamate] and the insecticides aldrin [1,2,3,4,10,10-hexachloro-1,4,4a,5,8,8a-hexahydro-exo-l,4 endo-5,8-dimethanonaphthalene], heptachlor [ 1,4,5,6,7,8-heptachloro-3 a.4.7.7a-tetrahydro-4,7-methanoindene), and carbofuran [2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate] to determine the effects of these chemicals, alone and in combination, on germination and emergence. All seed lots were treated at the same time and were planted 10,30, and 50 days after treatment at 30-mm depths in soil (a silty clay loam, typical of Turkey's Anatolian Plateau) at a greenhouse in Ankara, Turkey. After the first day of emergence, seedlings were counted daily for 7 days. Aldrin, heptachlor, and carboxin did not reduce seedling emergence. Benlate reduced emergence 17, 18, and 23% in Bezostaya, Bolal, and Köse 220/39, respectively, when seeds were stored for 50 days and seedlings counted 11 days after planting. Carbofuran decreased emergence as the storage period increased, especially in Köse 220/39. Carbofuran was the only pesticide that was consistently more phytotoxic when rates were doubled or tripled. Combinations of carboxin with either aldrin or heptachlor did not generally reduce emergence. However, all combinations involving carbofuran reduced emergence more than carbofuran alone. Cultivars varied in susceptibility to fungicides and insecticides. Bolal, a hard red winter wheat from Nebraska, showed the most tolerance. Seedling emergence of Köse 220/39, a Turkish variety, was reduced 13 to 19% more than was Bolal at the 11-day seedling count in all seed treatment storage periods. Seedling emergence of Bezostaya, a Russian variety, was intermediate between Bolal and Köse 220/39. Adverse effects of pesticides that reduced emergence were more evident as storage time increased. Results indicated that benlate and carbofuran, used alone or in combination, reduced seedling emergence. Less phytotoxicity resulted if seeds were planted as soon as possible after treatment.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .