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Herbicide Carryover to Fall Established Cover Crops

Aug 26, 2022

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By Alyssa Essman

Establishment is one of the most important factors in the management of a cover crop for weed suppression. With later planting dates this year followed by a very dry June, conditions were right for herbicide carryover to be a concern for fall planted cover crops. The increase in precipitation events throughout July likely decreased that risk. It is still important to consider which herbicides were used during the growing season when selecting cover crop species. Potential interactions between cover crops and herbicide residue were covered in depth previously in this article (hyperlink to https://agcrops.osu.edu/newsletter/corn-newsletter/2020-29/herbicide-residue-considerations-fall-cover-crop-establishment).

Herbicide persistence is difficult to predict and varies by field and year. If there are specific concerns, it is best to perform a field bioassay now to determine potential impact of herbicide residues. To do this, collect soil from the fields where carryover is a concern, and soil from a field with no herbicide residue and a similar soil type. Plant cover crop species in each soil, water, and monitor emergence after 2-3 weeks. If emergence and plant health look similar between the soil with and without the herbicide, it is likely that the cover crop can be planted without risk of injury.

crop

Cover crop planting

There has been some discussion amongst weed scientists over the benefit of a cover crop with reduced stand or biomass due to herbicide residue versus no cover crop, and whether a reduction in plant health has any effect on the ability to suppress weeds. More research is needed in this area. What we do know for certain is that high levels of biomass and ground cover provide the most effective weed suppressive benefits. Cereal rye tends to be the most effective species for weed suppression and is also the least sensitive species to herbicide carryover.

For more information on herbicide carryover to fall established cover crops, check out: https://iwilltakeaction.com/uploads/files/20210623-factsheet-cover-crop-carryover-usdadraft.pdf

Crop Observation and Recommendation Network

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.

Source : osu.edu

Video: Spider Mite Control with Predatory Mites (Neoseiulus californicus)

The predatory mite Neoseiulus californicus is an effective natural enemy of various species of spider mites, including the two-spotted spider mite (Tetranychus urticae). As a key player in biological pest control, this predator helps growers protect their crops sustainably.

How does Neoseiulus californicus work?

•Specializes in targeting the larval and nymphal stages of spider mites.

•Also consumes spider mite eggs, ensuring population control.

•Detects prey through webbing and leaf damage rather than sight.

•Feeds by sucking out the contents of its prey.

Why use Neoseiulus californicus for spider mite control?

•Highly adaptable to different environments, including warm and dry conditions.

•Works as both a preventive and curative solution for spider mite infestations.

•Complements other predatory mites, such as Phytoseiulus persimilis, for integrated pest management (IPM).

•A natural, sustainable alternative to chemical pesticides.