Vol. 9, Special Issue 10, Part O (2025)

Field experiment on Seasonal occurrence of Rhopalosiphum maidis (Fitch) and coccinellids on maize crop was conducted during rabi season of 2021-22 at Entomology farm, BACA, AAU, Anand. During seasonal occurrence study, maize aphid species R. maidis was noticed from last week of December, 2021 to first week of March, 2022. The aphid infestation on the tassel began in the fourth week of December, progressively expanded and peaked (561. 8 aphids/tassel) in the fifth week of January (5th SMW). Similarly, an aphid infestation on cob began in the first week of January, 2022. Its population was initially low, but it gradually increased in numbers and peaked in the fifth week of January with 472.2 aphids/cob (5th SMW). The incidence of aphid declined from 1st week of February. Aphid infestation showed non-significantly negative correlation with maximum temperature. The minimum temperature had a very highly negative correlation (r=-0.81**). Aphids and relative humidity correlated positively in the morning and negatively in the evening. The activity of coccinellids was observed from 4th week of December to 1stweek of March. In January, the fifth standard meteorological week (for grubs) and the fourth standard meteorological week (for adults) both observed relatively higher population of coccinellids on tassels (2.24 grubs/tassel and  2.22 adults/tassel). Similarly on cob, activity of coccinellids observed during 1st week of January to 1st week of March. The higher population of coccinellids on cob was observed during 1th week of February for grubs (2.00 grubs/tassel) and 5th week of January for adults (2.22 adult/tassel). Decreasing trend of population of coccinellid grub was found from 1st week of February to 1st week of March and 5th week of January to 1st week of March for adults