Efectividad de nueve insecticidas en el contrarresto de Epitrix sp. (Coleptera: Chrysomelidae) en cultivos de papa, en Ecuador

Abstract

The flea beetle, Epitrix sp. is an insect pest affecting early foliage of potatoes in Ecuador. A field test was conducted at Santa Catalina Experimental Station to determine the initial and long lasting effectiveness of DDT, Dieldrin, Aldrin, Malathion, Sevin, Toxaphene, Diazinon, Metoxychlor and Dipterex. The experiment was set up in a randomized block design with 5 repetitions. The insecticides were sprayed as suspensions at the rates of 3,5 - 1,25 - 1,25 - 2,0 - 3,0 - 4,5 - 1,25 - 3,5 and 3 pounds of technical material per hectare, respectively of the above mentioned chemicals, when plants were 12 days old. Results were measured by periodical beetle counts in 25 buds and its 2 basal leaves in each of 25 plants per plot up to 31 days from the spray. Counts were made from 10 a.m. to 1:30 p.m., the period previously established as the best for the presence of the adults. Results indicate that Dieldrin significantly lowers the flea beetle population up to 31 days; DDT, Aldrin, Malathion and Taxophene did so up to 24 days; all insecticides excepting Metoxychlor and Dipterex depressed significantly the total population registered during the 31 days in comparison with the check