Abundance of Aphids on Various Canola Genotypes and Role of Abiotic Factors in its Population Fluctuation
Waseem Akbar, Muhammad Usman Asif*, Raza Muhammad, Muhammad Hamayoon Khan, Moula Bux
Plant Protection Division, Nuclear Institute of Agriculture, Tandojam-70060, Sindh, Pakistan
Brassica crops are the most diversified and largest oilseeds produced in the world. Different species of aphids are the most destructive pests of these crops due to sucking of cell sap from leaves, stem, flowers and pods limiting the crop yields. A field experiment was conducted to determine the relative tolerance of 28 canola genotypes against aphids and the effect of different abiotic factors on the aphid incidence from late January to late March at fortnightly intervals. Data inferred that all the evaluated genotypes had varying degree of tolerance to aphids and none of them was found completely immune. The abundance of aphids on different sampling dates and seasonal means differed significantly among the tested genotypes. The lowest aphid population per plant was observed on genotype NR-18 (11.11), whereas the highest on genotype NR-11 (89.22). For grain yield, genotype NR-18 gave the maximum productivity (3028.57 kg/ha) and NR-11 yielded the least (1409.11 kg/ha). Furthermore, highest aphid population (95.60 per plant) was recorded during the mid of March. The abundance of aphids showed non-significant association with mean temperature, humidity and sunshine. Our result suggests that tolerant genotypes can be grown as a component of an integrated pest management strategy for protecting the crop from aphid infestation and to reduce the use of expensive, toxic and environmentally damaging pesticides.