Suitability of different maize hybrids for development of Plodia interpunctella (Hübner)

Abstract

Plodia interpunctella (Hübner), the Indian meal moth (IMM), is a major lepidopteran storage pest worldwide. IMM larvae can be found in high abundance in stored maize and cause huge losses in seed germination and seed viability. This work aimed to assess the susceptibility of six maize hybrids (NS 6140, NS 640, NS 1090, NS 444 - dent type, NS 620k - pop-corn type, Red-aleurone maize - maize with an altered aleuron color) to IMM attack and suitability for pest's development. Standard laboratory diet (SLD) was used as a positive control. Under laboratory conditions, the following IMM life history parameters were monitored: larval mortality, mean developmental duration (egg to adult), adult emergence, adult lifespan and female fecundity. Kernel susceptibility was determined based on the Susceptibility Index (SI). The highest mortality of IMM larvae was on NS 620k (35.25%) compared to the other maize hybrids (11.2-19.5%). The highest number of emerged adults was on Red-aleurone maize (17.5), and the lowest on NS 620k (4.0). The longest lifespan was recorded for moths reared on NS 6140 and NS 640 (8.5 and 8.7 days, respectively). The highest female fecundity was on SLD (115.8 eggs), on Red-aleurone maize (44.3 eggs), while females reared on NS 620k laid the lowest number of eggs (22.8 eggs). Moths reared on NS 620k had the shortest body sizes (0.9 cm), which indicated reduced moths fitness. SI showed that Redaleurone maize (SI=7.79) was the most susceptible to IMM attack, while NS 620k (SI=3.08) was the least susceptible.