Evidence on non-pest status of Melanagromyza sojae (Zehntner) in Soybean

Soybean cv. PS-1042 was sown in two individual blocks, in one, phorate (10 G) was used for controlling tunnelling caused by Melanagromyza sojae while other block was left untreated. At harvest, one plant was randomly selected from each block for investigating correlation between % tunnel length in main stem, branches or whole plant and yield parameters. In untreated and treated blocks, % tunnel length in main stem and branches failed to show significant relationship with height of the plant, seed weight/plant and weight/seed. Similar relationship was also recorded in whole plant. Combined analysis of 400 plants from untreated and treated blocks indicated that tunnel length in main stem, branches and whole plant reduced the height of the plant but failed to influence the seed weight/plant and weight/seed. A study on frequency distribution of yield parameters in relation to % tunnel length in main stem, branches and whole plant failed to show any definite trend except a reduction in height of the plant. No significant difference was recorded in seed weight/plant and weight/seed of untreated and treated plots. Thus, it was apparent that no insecticidal treatment was required for the control of M. sojae.