Last week the question was: What is on this soybean leaf?
These are kudzu bug eggs. Just a few years ago kudzu bugs seemed like they were going to be a major pest in soybeans in the southeast; however, they haven’t been nearly as much of a problem lately. Beauveria bassiana is a fungus that has done a great job of keeping kudzu bugs at a manageable level. Thanks to this fungus, we rarely need to treat for kudzu bugs now. For more info on kudzu bugs, take a look at this video.
Here is this week’s question: What kind of spider is this?
More loopers are showing up in the sweep nets. We’re getting in to the time of year when we really need to keep an eye on them. Make sure you or your scout can tell the difference between a soybean looper and a cloverworm. Both move with a “looping” motion and can be the similar in color, so pay attention to the number of abdominal prolegs.
Correctly identifying is important because treatment options differ greatly. We have a hard time killing loopers with pyrethroids, so more expensive materials are needed. Cloverworms rarely cause significant damage on their own and can be controlled with low levels of pyrethroids. Misidentifying cloverworms for loopers will cost a grower money for a treatment they may not have really needed.
Make sure to scout every field on a regular basis. Failing to do so could cost you money as well. The photo below is a good example of what could happen in a field that is not scouted regularly.
When making treatment decisions, use the thresholds in the tables below. In order to make the most of your money, identify pests correctly and don’t spray until you’re at the thresholds. For insects not specifically mentioned in the tables, use the 15% foliage loss threshold.
We have a lot of good yield potential out there right now. It’s easy to let the hot weather and high humidity keep us out of the fields, but now is an important time to know whats going on in every field.
For more info on insect control in soybeans, take a look at the 2017 SC Pest Management Handbook.
The following update was prepared by Clemson Peanut Specialist Dan Anco.
What is the treatment threshold for threecornered alfalfa hopper? Good question. At this point we don’t really have a good answer linking insect or girdling counts to economic yield impact. Still, most of the products labeled for threecornered alfalfa hopper (TCAH) are broad spectrum insecticides.
Threecornered alfalfa hopper
While more of a concern during periods of hot dry weather, products like these have the potential to kill beneficial insects and flare spider mites. Because of this I would probably err on the side of caution in most cases where the risk of damage from TCAH may be questionable. Fields with large to excessive amounts of vine growth (irrigated fields, most Virginia types or some of the larger runners) probably can tolerate more TCAH than fields with less growth.
Vine girdled by threecornered alfalfa hopper. Photo by Dan Anco.
If peanuts are starting to show signs of manganese deficiency near 95 to 100 DAP (about 20% of plants), would it payoff to apply additional manganese if it previously went out at 60/75 DAP? At this point I would not add additional manganese. Some of the new growth may currently be showing manganese deficiency, and adding more Mn may green the leaves up some, but at this point in the season more Mn hasn’t been linked to improved returns. As we get closer to the tail end of the season, peanut leaves can start to show signs of nutrient stress when they are supporting a large crop, since more of the nutrients are flowing to the developing seed.
Most of the crop continues to look good. As these next few weeks roll out, keep an eye out for late leaf spot lesions and then pod maturity.
A fair amount of corn was harvested last week. Yields are looking good so far and we hope that trend continues.
The moisture is around 27% in this field, so the corn is heading to the dryer.
Rains are moving in this week and we are forecast to get 2-3 inches over the next 5 days in most places around the Pee Dee. This will bring the combines to a screeching halt until all the rain clears up. We need the rain on our other crops, so it’s not completely unwelcome.
Stink bugs came in early in some places and disease came in late. Regardless, we’re looking at our second straight year of good corn.
Last week the question was: What happened to these soybeans?
These soybeans are showing damage symptoms from an auxin herbicide, dicamba to be more specific. We’re seeing these symptoms show up in a number of fields right now. Some volatilization is suspected to have occurred a few weeks ago when it was so hot and humid. Drift is also to blame in a number if instances. Please be mindful of the weather when applying auxin herbicides and always follow the label. If problems continue to arise, the EPA may revoke the registration of these new products.
Here is this week’s question: What predatory insect is hiding in this photo?
Stink bugs are the main pest to look out for in cotton right now. There are plenty of them around in places and plenty of insecticide applications are going out. Here are a couple photos below to remind folks of what stinkbug damage within the bolls looks like.
In Clemson Entomologist Jeremy Greene’s latest Cotton/Soybean Insect Newsletter, he stresses the importance of being able to distinguish the species of stink bug you have in your fields. The brown stink bug is widely resistant to pyrethroids, so if a large proportion of the bugs you are seeing are browns, then an organophosphate (like Bidrin) needs to be added to the tank.
The photos above from Jeremy Green show the juveniles and adults of the Southern green stink bug (left) and the brown stink bug (right). Being able to distinguish the juveniles is equally important as it is for the adults.
Remember when making treatment decisions that the threshold for stink bug damage changes throughout the season. It’s important to record when each field begins blooming and to always keep up with which week of bloom you are in currently.
Take a look at page 116 in the SC Pest Management Handbook for more info on scouting and treating for stink bugs.
Last week the question was: What are the bugs all over the side of this dock?
These are mayflies. Mayflies spend the majority of their lives in the water as nymphs feeding on algae and organic matter. After 1-2 years they pupate into adulthood and leave the water to mate. Adults lack mouth parts and well developed digestive systems, so they have only a day or two to mate and lay eggs before running out of energy.
Here is this week’s question: What happened to these soybeans?
A number of fields have reached physiological maturity and a lot more are approaching rapidly. Folks are busy getting their combines ready to roll now and it won’t be long before we see corn harvest starting on a wide scale. You can see the black layer at the tips of the kernels pictured below.
Here is an internal view of a kernel sliced in half. The black layer is just under the tip.
We have a pretty decent corn crop out there, though there is a ton of stink bug damage in places. The first 12-15 rows of some fields are completely trash. Growers may need to cut end rows separate from the rest of the field in some places to avoid mixing rotting kernels in with good corn. There is some Aspergillus (aflatoxin) out there too.
There is plenty of good stuff out there. The ears below had excellent pollination all the way to the tip. Most of the ears in the field were the same way.
There are a few chances for rain in the forecast, so our biggest challenge from this point on will be getting the corn dried down and getting it out of the field. Our overall crop probably isn’t as good as the 2016 crop, but it’s miles ahead of where we were in 2015. We’ll have a better picture of that once the combines start rolling.