Focus on late season cotton pests at CSD web

04 Feb '06

3 min read

Cotton Seed Distributors Ltd (CSD) announced that the presence of various late-season insect species in cotton crops has been reviewed by a team of industry entomologists on the weekly CSD Web.

Paul Grundy, a research entomologist with QDPI&F at Biloela said whitefly populations were much higher than at the same time last year due to more favorable weed biomass during the wetter winter-spring this season, which means a higher proportion of fields may require treatment, despite the presence of whitefly parasites.

He said mirids had also been a problem in central Queensland, with most fields requiring two to three treatments, but secondary pests such as mites and green vegetable bugs were not yet a major issue, but could develop as the season progresses.

Jassid numbers have been much higher this season, and have been a consideration in some spray decisions.

Heliothis numbers have varied during the season, with some points of heavy pressure, but numbers have tailed off in the last 3-4 weeks.

David Murray, Principal Research Entomologist with QDPI&F at Toowoomba said mirid activity had been relatively high, also prompted by rainfall, weed growth and alternative host crops, with some cotton crops requiring regular treatments.

“There has been some concerns about the high levels of damage sustained, and lack of fruit retention caused by rapid re-infestation and residual populations of mirids following treatment.

“I think there is general agreement that using a beat sheet is certainly the most accurate way to detect mirid populations. They are particularly good for picking up nymphs. First and second instar nymphs are quite tiny and easily missed visually.”

More Cotton Seed Distributors Ltd News... More Textiles News - Australia...