The attack of pea stem fly is maximum in the month of . . . . . . . .

The attack of pea stem fly is maximum in January.
Pea Stem Fly (Ophiomyai phaseoli) is a major pest of a pea. The maggots bore inside the stem leading to wilting of the plants.
The damage is more severe on seedlings than on grown-up plants. The adult flies are metallic black. They are active in summer and mate 2 - 6 days after emergence.
Incubation, larval and pupal periods last for 2 - 4, 9 - 12 and 18 - 19 days respectively, during November - December thus, causing maximum damage in January as they are adults by that time.
The average longevity of males is 11 days; however, females can live up to 22 days.