Seasonal Incidence of Major Insect Pests in Relation to Abiotic Factors in Mustard

Aim: The present study was under taken to the know the incidence of major insect- pests of mustard and their correlation with abiotic factors.

Study Design: Randomized Block Design (one factor anova).

Place and Duration of Study: Regional Agricultural Research Station (RARS), Palem, Nagarkurnool district, Telangana state during rabi, 2023-24 between November to March.

Methodology: The field experiment was conducted at RARS, Palem using the variety DRMRIJ 31 with spacing of 45cm× 15 cm. Observations were taken timely from the start of the pest incidence to till harvest of the crop at weekly intervals (Standard Meteorological Week). The incidence of insect pests and their natural enemies were individually correlated with the weather parameters.

Results: The highest population of mustard aphids at 6th SMW (9.65 aphids/10cm apical shoot), leaf webber at 3rd SMW (5.70 larvae/plant), flea beetle at 52nd SMW (1.78beetles/plant) painted bug at 3rd SMW (1.20 bugs/plant) mustard sawfly at 52nd SMW (0.22 grubs/plant), predatory ladybird beetle peak at 4th SMW (0.22 beetle/plant). The correlation studies of the pests with weather parameters revealed that maximum temperature positive non-significant correlation with leaf webber, painted bugs and coccinellids, non-significant negative with sawfly, significant positive with aphid and negative with flea beetle. Minimum temperature was non-significant negative with leaf webber, aphids, painted bugs, flea beetle, sawfly and coccinellids. Morning relative humidity was positive correlated with painted bug and flea beetle, negative non-significant with leaf webber, sawfly and coccinellids and negative significant with aphid. Evening relative humidity was positive non-significant with leaf webber and sawfly, negative non-significant with painted bug and coccinellids, positive significant with flea beetle and negative significant with aphid. Sunshine hours positive correlated with leaf webber, aphids, painted bugs, sawfly and coccinellids and negative non-significant with flea beetle.

Conclusion: Seasonal incidence of insect pests in crops is closely linked to weather parameters such as temperature, humidity and sunshine hours. Understanding these relationships is crucial for effective pest management and crop protection.