Planting progress; beware frogeye, slugs


Tony Nye - OSU Extension



Finally … we got some dry days of weather that allowed many farmers to get some crops planted this week.

We still have a ways to go, but nice for progress this planting season. Unfortunately there is still rain in the forecast which will cause more delays to planting.

We are very fortunate, however — there are many counties along the western border and the northwest portion of the state that still have less than 10 percent of their crop planted due to excessive rain.

Anne Dorrance, Ohio State University plant pathologist, suggests thinking about the situation we are moving into for those fields that will be switching from corn to soybean. She notes we are quickly moving to continuous soybean on 50% of Ohio Soybean acres.

This is not an ideal situation as it leads to the rapid build-up of soybean cyst nematode (SCN), residue pathogens of frogeye leaf spot and soil borne root rot pathogens.

So as you’re making this decision, look at the history and sit down with your variety listing. If you had frogeye leaf spot last summer in a field, this would not be ideal to move to continuous soybean — Dorrance has lots of research proving it is not a good situation with disease history the year before.

Chances are you will have more disease issues again this year. If you must, then only plant a variety with high levels of resistance to frogeye leaf spot. If you are moving into 5 years or more of soybeans, her big question is: When did you last pull soil for a SCN test?

We are picking up quite a few fields (>50%) in Ohio with populations of SCN that are adapting to the primary source of resistance that companies have incorporated into their germplasm (PI 88788, R3). Continuously planting this one type of resistance will push the adaptation much faster to this source of resistance.

Again this year there is opportunity to test fields for the presence of SCN. If you would like to sample some of your farm for SCN, I can help.

Through special funding I can help you get your fields checked at no cost to you. Contact me at 937-382-0901 or nye.1@osu.edu and I will set up a time to get samples pulled.

Finally this week, Kelley Tilmon and Andy Michel, Ohio State University entomologists, warn producers that the cool, wet conditions we have had this season is the perfect weather to favor slug populations.

Slugs are able to eat many types of plants, and even in fields that haven’t been sown yet slugs can successfully feed on weeds.

Late planting in many areas may cause more slug headaches than usual this year – as slugs get geared up, the small size of both soybean and corn will lead to a greater damage potential from them.

Although they do not know how numerous slugs are in fields, they do know that most crops are being planted later than normal – a perfect situation for more slug damage than usual.

If you have read previous OSU recommendations for slug management, you know that one way a grower can get a head start is to plant early, and get their crop out of the soil and growing before slugs begin their heaviest feeding.

However, with the weather conditions over the past month, many fields are just now or even not yet planted. Slugs have been hatching and beginning to grow; this will result in many fields just germinating or emerging when slugs start to feed.

This combination of feeding slugs and small plants can result in much more plant injury that normal. Slugs can also damage un-germinated seed.

Thus, growers with a history of slug problems who are just now planting into those fields should watch their crops closely over the next few weeks.

Although all fields should be scouted, focus on those with a history of these pests, where weed control was less than effective, or with a lot of residue left on the field.

Slugs are nocturnal so you may not catch them in the act of feeding unless you inspect plants after dusk. If you see feeding damage on plants, sift through residue and look under stones in the field.

An asphalt shingle laid out on the ground, painted white to keep it cooler, is also a good sampling device. Slugs will collect under it during the day.

We do not have research-based thresholds for slugs in field crops. However, if the level of damage concerns you a rescue treatment may be in order.

There are few products available, but three of them are Deadline MP, Iron Fist, and Ferrox, which are all baited pellets which must be broadcast and ingested by the slugs.

Tony Nye is the state coordinator for the Ohio State University Extension Small Farm Program and has been an OSU Extension Educator for agriculture and natural resources for over 30 years, currently serving Clinton County and the Miami Valley EERA.

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Tony Nye

OSU Extension