Seasonal abundance' of certain biocontrol agents associated 'with aphids in wheat fields was studied throughout 1992/93 wheat ,/,season. Three aphid species were recorded infesting wheat plants 1~,t\' during the study. The highest rates of aphid infestation were
, observed during March and April. Four groups of insect predators were counted. Highest numbers of predators were recorded during
the period prolonged from the end of March to the beginning of April. Coccinellids and chrysopids were the most abundant
a
preqtory species in wheat fields. The maximum parasitism % was
estimated at the end of April. Two hymenopterous parasitoids and one hyperparasitic species were identified. Rates of parasitism were increased by planting flowering plants around wheat plots, and that was associated subsequently with certain decrease in aphid counts and increase in the obtained yield. Calandula was recommended to be cultivated around wheat plants, as in this case higher numbers of aphidophagous insects, lower aphid infestation
and higher grain yield were recorded.
N umbers of aphidophagous insects were also counted on 10 different wheat varieties. Data indicated variations in the counted numbers which were highest on Pick variety, followed by Copper
and Serren varieties.
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