Abstract
Present study was planned to determine the yield loss in wheat crop at different dates of observation for the population of aphids. The wheat cultivar BK-2002 was sown at Arid Zone Research Institute, Bhakkar. For two different treatments viz. sprayed and un-sprayed wheat crop was compared, sprayed crop was observed with minimum aphid’s population whereas un-sprayed appeared comparatively susceptible with maximum population of aphids. Thiamethoxam (Actara®) was used as insecticide for sprayed treatment @ 25 gm/acre as recommended commercially. Last week of February was found to be very favourable for aphids in wheat fields in the study area. Third week of February was found to be the most suitable period for the bio-control agents i.e. Coccinellids in wheat crop. Positive correlation was found to exist between the population of aphids and Coccinellids among different wheat cultivars.
Highlights
Wheat (Triticum aestivum L.) is a major crop with largest area under cultivation in Pakistan and plays a significant role in economic stability of the country [1]
Present experiment was performed at Arid Zone Research Institute (AZRI), Bhakkar, Pakistan during 2004-05 to see yield losses in wheat crop infested by green aphid
First detection of aphids on the wheat crop was observed on 11th of January 2005 (Table 1); at this time, the population was 0.18 aphid/ plant, afterwards a gradual increase in the population was observed that reached to its peak in the mid of March (51.55 aphid/plant)
Summary
Wheat (Triticum aestivum L.) is a major crop with largest area under cultivation in Pakistan and plays a significant role in economic stability of the country [1]. Low yield of wheat per hectare in Pakistan compared to the other advanced countries is due to several abiotic and biotic factors, such as traditional methods of cultivation, varieties, lack of irrigation facilities, barani areas, soil fertility and incidence of insect pests and diseases. Many insect pests attack wheat (Triticum aestivum L.) in Pakistan, severe damage is caused by aphids. Aphids cause yield losses either directly (35-40%) by sucking the sap of the plants or indirectly (20-80%) by transmitting viral and fungal diseases [2]. Population density of aphids depends on the abiotic factors [3,4,5]. During spring season (February-March) aphid population increases, at the same time biocontrol agents like coccinellids increase as natural check on this pest [6]
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