Monthly Archives: August 2017

Pecans: Black Aphids & Mites

Reports here are that black aphids are out but numbers are not necessarily high yet.

UGA Extension Entomologist Dr. Will Hudson has this INSECT update for us:

Black Aphid damage

Black Aphids

Growers across the state are seeing an increase in black aphids. For growers with old Schley trees this has been going on for a while, but the other susceptible varieties like Sumner and Gloria Grande are experiencing a build-up now.  Remember, if you see nymph clusters you need to take steps to protect your foliage and avoid the kind of damage that can affect your crop next year.  Imidacloprid still controls black aphids pretty well, but requires the higher rate on the label (several formulations are available; the 2 lb materials need 5.6 oz/acre).  Other neonicotinyls like Belay and Assail are also effective.  If you also have yellow aphids then Carbine, or Fulfill would control both. Closer is one of the most effective options at the moment.

Mite damage on pecan leaf

Mites

We are also seeing some mite flare-ups in scattered orchards. Mites can be controlled with abamectin products (Agri-Mek, Abba Plus, etc.), Portal, Acramite, or Nexter.  The Nexter will get both aphids and mites, and may be a good choice where those pests are present and a weevil spray is needed or likely. Check labels for rates and surfactant requirements.

Insecticide Rainfast?

Dodging showers can be a challenge if you need to treat lots of acres with few sprayers, and sometimes the rain catches you or pops up right after application. If it starts to rain while you are spraying, stop the sprayer.  It will do little good to apply an insecticide (or fungicide) that will be washed off immediately.  If the rain comes after you finish, you may be okay if the spray has dried on the leaves.  A good rule of thumb is that if you get a rain within 1 hour or less of spraying and you will need to retreat.”

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Filed under Entomology, Pecans

Row Crop Disease Update

In cotton this week checking whiteflies, we are reaching treatable thresholds by the way… I am also seeing some target spot in RANK cotton. Also, it is very low on the plant and is not moving up. Cotton I’ve looked at is 4th and 5th week of bloom. Below is a current disease update from UGA Extension Pathologist Dr. Bob Kemerait:

Cotton

The current weather is very favorable for development of target spot and also spread of bacterial blight.  To date, bacterial blight is only a problem in susceptible varieties…The season is not over yet, and things could change.

Target Spot seen in ‘rank’, irrigated cotton, but on the very lower leaves.

TARGET SPOT:  In some, but not all, of your trials  target spot is a significant issue. From your trials, some varieties are CLEARLY for susceptible. Conditions we have now are perfect for it.  Should every grower spray every field for target spot?  NO!  But growers SHOULD BE AWARE. In one field, target spot was becoming established, and I told him I would likely treat the field with a fungicide. In another field, no target spot was found and I told him I would not treat that field.

Peanuts

We are at a critical point in the peanut season. Reports of white mold in fields are coming in every day and I am receiving some reports of leaf spot. I don’t know of any fields where leaf spot is “out of control” and only one field where white mold is “breaking loose”.  However, both diseases can be explosive given the right environment and time to become established. Growers should stay on an appropriate fungicide program for these diseases and also Rhizoctonia limb rot. Timeliness and coverage are CRITICAL.

Soybeans

Asian soybean rust has been puzzling this year. We found it in kudzu very early in the season, yet to date it remains confined to kudzu in our southern tier of counties. I still expect soybean rust to “break out” as southern corn rust has done, but I can’t understand what it is doing now. Fortunately, our Sentinel Plots are being monitored, so we can keep you up-to-date. Even though the disease has been slow to develop, I still believe that there is merit, especially in southern Georgia, to protect the soybeans during late-bloom/early pod set, especially when applying something like dimilin and boron. There are other diseases, such as frogeye leaf spot, which can be problematic and that can be managed with the same fungicides at the same time.

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Filed under Corn, Cotton, Disease

Pond “UFO”?

We were looking at some pond weeds this week and saw an Unidentified “Floating” Object. Well, it wasn’t exactly floating. But it looked like Jell-O sitting on the bottom. We picked it up and set it on the ground. It’s texture was like a jellyfish. We cut it into also.

It turned out to be an invertebrate animal referred to as ‘Bryozoan colonies.’ UGA Extension Aquatic Scientist Dr. Gary Burtle says Bryozoans live in relatively clean water. Does it have any relation to fishing? Dr. Burtle says:

They may indicate that the bream population of this pond is not very abundant. Ask about fishing success and if bream are caught.  Sometimes, in a bass overcrowded pond, the bream population is so low that these invertebrates can thrive.

Bryozoan invertebrate from a pond

Bryozoan cut in half

You may have seen these before. This is one of those, ‘you learn something knew everyday.’ The Smithsonian Marine Station has more information.

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Filed under Aquatic Environments

Foliage Feeding Caterpillars In Peanuts

We’ve been treating for worms in peanuts now. I’m seeing some loopers mostly. But there are reports of tobacco budworm, and I do see some TBW moths flying. We need to be scouting when we are in the field. The biggest question is our threshold.

Egg mass from armyworms (left); and ‘windowpane’ feeding (right)

Threshold

For foliage feeding caterpillars, our threshold is 4 – 8 per row foot. Remember, peanuts can tolerate a significant amount of defoliation with no impact on yield, but when we start to see ragged leaves, it becomes difficult to hold back. Our peanuts look really good thanks to timely rainfall. When peanuts are not stressed, we can go closer to 8 on the threshold.

Caterpillars feeding on blooms?

This was in issue a few years ago where UGA Extension Entomologist Dr. Mark Abney had this to say:

Bloom feeding has been observed in peanut for a number of years, and current thresholds do not take this type of damage into account. Peanut produces a lot of blooms, and not all of them will result in harvestable pods even in perfect conditions. The impact of caterpillar feeding on blooms is not known. I think it is reasonable to be more aggressive in making treatment decisions when significant bloom feeding is observed. What is “significant bloom feeding”?  That is a question that will have to be answered on a case by case basis taking into account the condition of the field, number of caterpillars, maturity of the crop, and personal experience

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Filed under Entomology, Peanuts