Corn Stage – Still in the bag only a few acres in.  At least 10 days for some folks to get manure spread.  At this point the goal is get the corn in the ground then worry about the weeds and insects. Pests cutworms around. Got some calls on vegetable crops. I would expect slugs and numerous other pests to be waiting to be fed a nice crop of corn.  Again get the corn seeded and protected then worry about weeds. I see a tremendous bottle neck coming in another week with alfalfa ryelage and manure spreading with time management. Start with what makes the most money. High quality alfalfa and corn seeding before the 10th of May.  Focus on that. Other – Soybeans Stage Fields too wet to do anything at this point.  Once the field can be driven on I would plan to get it planted immediately then worry about weed control later. Pest ·        Weed  – Burndown failures are evident where Gramozone is being used to kill rye, barley and wheat. The issue here is that  this product is contact therefore it needs complete coverage to be effective.  10 gpa application rates hinder the product as does waiting until the crop is too tall to cover the entire plant.  Resprays are occuring as a result. ·      Disease

·      Insect

·        Other –.    Alfalfa Stage   10 inches of regrowth in many fields far behind last years growth.  There are 475 heat units that apply to alfalfa historic accumulations of 700 heat units so we behind by about two weeks.   Harvest would be ideal at 700 heat units so we need some heat soon to push this further.

·        Established Stands – 10 inches ·        Spring Seedings o   2 inches Pest ·        Weed o   Add ·        Disease ·        Insect  o   Weevils are  active I did see some sign in area fields nothing too prolific at this point.  .

o   ·        Other o   Add Tall Grass Hay Stage  Growing rapidly Established –  10 inch regrowth New Seedings 3 inches in many cases if they were able to get in to seed this spring at all. Pest ·        Weed o   Perennials are at full speed in growth. Application selection of Cimarron, Forefront, Milestone, Crossbow, 2,4-D, Stinger, Overdrive, or combinations should be made on a case by case basis with reseeding/overseeding and species in mind.    ·        Disease o   None to report ·        Insect –  Still numerous grubs found in area fields. In hay crop it is not as big of an issue as pasture and heavily manure fields. ·        Other Small Grains Stage Stage 6 or 7 in most areas with most early planted approaching stage 6. Pest o   Disease – Now is the time to get out and begin looking for disease movement. With rains septoria will begin infection.  Be sure to check for the presence on the lower leaves and not it as the season progresses then see how much it moves toward the flag leaf it it gets up to within three leaves of the flag a fungicide may prove to be economical and prevent spread to the flag leaf. o   Insect ·        Reports of Cereal Leaf beetle showing up in areas to the south.       o   Other Pasture                                                                                             Stage Green Up 10inches of new growth. Established – Wait until the grass has about knee high growth before grazing.  If need be flash graze quickly to keep ahead of the grass.  New Seedings – 3 inches of growth Pest ·        Weed o     Again as in the hay crop selection is critical.  Forefront, Cimarron, Overdrive, Crossbow and Milestone do not have a grazing restriction for most species in the region. ·        Disease o   Add ·        Insect

o     Got some more grub calls from Growmark. Seems to be some populations around.  I would not get excited since rains tend to decrease the effect of the grubs.

Entomologists hesitate to answer

May 1, 2008 12:00 PM, by Fae Holin

Given the current high hay prices, growers should scout for alfalfa insects diligently. But should they treat at lower-than-recommended economic thresholds?
“The entomologists don’t really have an answer,” says Mark Sulc, Ohio State University extension forage specialist. Sulc asked insect specialists from several states whether they’d recommend lowering insect thresholds because of hay’s higher value.
“The answer is that there is not going to be a good answer, at least not right away,” replies Kevin Steffey, University of Illinois extension entomologist.
“We were happy to go along living with the current thresholds when commodity prices were low and nobody challenged them,” says Steffey. “But now, suddenly, the commodity prices of field and forage crops have turned around dramatically and we’re being asked questions that we’re simply not prepared to answer well.
“Simplistically, if the commodity price doubles, the economic threshold is cut in half,” Steffey says. “My colleagues in research would take issue with that statement, but my rhetorical response would be: ‘What is the alternative? We aren’t going to tell people to go out and solve quadratic equations for insect numbers vs. yield’ … and, quite honestly, neither they nor we have the data.”
The data that is available was collected 30-40 years ago, when hay wasn’t considered a high-value crop, says Steffey. And anyone willing to do such laborious and time-consuming work would have a hard time getting funding for it today. Plus, the relationship between insect damage and price isn’t linear, Steffey and Sulc say.
But alfalfa weevil threshold data, while old, may still be viable, says Steffey. Alfalfa has changed little compared to corn and soybeans, which are much higher yielding than they were 10 years ago. Some entomologists have produced sliding scales adjusting alfalfa weevil and potato leafhopper thresholds based on commodity prices. But those, too, are now outdated, he adds.
Scientists also don’t want to adjust thresholds down because most of them are already on the conservative side, Sulc says. Thresholds are established to give growers time to react and make insecticide applications. Steffey adds that lowering thresholds “puts us into territory where the relationship between insect injury and yield is not known.”
“The potato leafhopper threshold is so low right now on stubble alfalfa that it is almost a no-brainer,” says Steffey. “Leafhoppers are either there or they’re not and they’re highly destructive.”
Potato leafhoppers are not generally a chronic problem most years in Oklahoma, says Phil Mulder, Oklahoma State University extension entomologist. “Populations of this insect typically overwinter in Louisiana and other southern regions. With spring wind trajectories, they get dumped into states like Nebraska and Iowa and to the east and north from there,” he adds.
Michael Rethwisch, a University of Nebraska-Lincoln extension educator, has witnessed its devastation. “I have never seen leafhoppers as thick in alfalfa as last year in the eastern third of Nebraska. But if you were in the middle third of the state, people there didn’t see them.”
Glandular-haired potato leafhopper varieties, less susceptible to hopper damage, can take thresholds higher than recommended, says Rethwisch. In Ohio, Sulc found that established stands of highly resistant varieties didn’t show economically significant and consistent yield loss until hopper populations were three times the normal threshold when 10-12 days of regrowth was present.
Rethwisch is commonly asked if it’s better to spray for leafhoppers or cut early. Cutting just forces the adults to find another field; spraying breaks the cycle. Growers have to determine if they want to endure the damage or try to stop it, he says.
He and Oklahoma’s Mulder are more concerned about alfalfa weevils. “Alfalfa weevil not only hits us with pretty heavy populations, it hits us incredibly early some years,” Mulder says. “We’d like to see growers go by a scouting method where they shake out 30 stems selected at random across a field, count larvae and use a degree-day-based model that looks at the number of degree days accumulated, the height of alfalfa and the infestation that they found in the stem sample.
“If they don’t want to scout, a rule-of-thumb threshold is one larva per stem,” he adds. But Oklahoma State makes things easier for weevil watchers. “In Ohio, natural enemies and diseases keep the weevil populations in check most years,” Sulc says. But he encourages Ohio growers to scout fields, since damaging populations do occasionally develop. “In contrast, damaging leafhopper populations are very common, especially in western Ohio,” he adds.
Rethwisch says growers need to monitor fields closely for weevils and leafhoppers. “Just because it’s alfalfa, don’t ignore it. Growers need to be on top of it. That didn’t happen last year and leafhoppers caught a lot of people unawares,” he says.