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Extension Entomology

Month: April 2019

Alfalfa Weevil Update

— by Dr. Jeff Whitworth and Dr. Holly Davis

Alfalfa weevil development is/has proceeded quite rapidly, and many fields have required an insecticide application.  Pictured here is a representative sample of alfalfa plants from a non-treated field and a close-up from that field.

Using the stem shake bucket method of sampling, this untreated field still had an average of 8+ larvae/stem at different developmental stages.  Plus, pupation had already begun in that field.

In contrast are the plants representative of a field that was treated on 5 April, which had already exceeded the 1 larva/ 2 stems, or 50% infested, treatment threshold.  However, larvae are still hatching and developing, and the feeding damage is starting to become apparent again.

 

Thus, alfalfa fields should continue to be monitored for at least another 10-14 days for the need of a 2nd insecticide application or, if possible, swathing.  If insecticide applications are deemed warranted, be sure to check the label for the pre-harvest interval (PHI) requirement for the insecticide used.

For more information regarding alfalfa weevil management please refer to the KSU Alfalfa Insect Management Guide:  https://www.bookstore.ksre.ksu.edu/pubs/mf809.pdf

Alfalfa Weevil Update

–by Dr. Jeff Whitworth and Dr. Holly Davis

 

Alfalfa weevil populations seem to have “exploded” around north central Kansas in the past week.  Tiny alfalfa weevil larvae were first detected in NC KS on 5 April, but probably a few started hatching a day or two prior.  However, the infestation levels that were detected on 5 and 6 April were all well below 10%, and mostly less than 1%.  In contrast, fields sampled on 16 April all greatly exceeded 100% infested using the stem shake bucket method and large numbers of different stages of larvae were detected.

 

 

To sample using the shake bucket method, randomly select individual alfalfa stems and quickly and vigorously shake them into a small white bucket.  Then, count the number of dislodged larvae in the bucket and divide by the number of stems to get the infestation level.  For example, 15 larvae from 10 stems = an average of 1.5 larvae/stem.  Do this in several areas throughout each field to get a good indication of the alfalfa weevil infestation level and the stage of development of the weevil.  One of the problems with the shake bucket method is that some stems have several larvae/stem while others have none (yet).  Thus, the infestation level may appear to be higher than is the actual infestation.

 

However, in NC KS, with as many larvae as there are already (with more to come probably) and as much damage as we are starting to see in spots, it may be prudent to treat fields as soon as possible.

 

For information on insecticides registered for use for alfalfa weevil control, please see the KSU Alfalfa Insect Management Guide: https://www.bookstore.ksre.ksu.edu/pubs/mf809.pdf

 

 

Common Asparagus Beetle

–by Dr. Raymond Cloyd

If you are growing asparagus then it is that time of year to be aware of the only insect pest of asparagus; the common asparagus beetle, Crioceris asparagi. Adult beetles are 1/4 inch long. The body is metallic blue to black with red margins and six cream-colored markings (Figure 1).

Figure1. Common Asparagus Beetle Adult (Author–Raymond Cloyd, KSU)

Adults emerge from the soil in early spring and fly to new asparagus shoots where they mate and feed. Females lay up to 30 eggs on the end of spear tips as they emerge from the soil (Figure 2)

Figure2. Common Asparagus Beetle Eggs on Spear Tip of Asparagus (Author–Raymond Cloyd, KSU)

Larvae hatch from eggs after about a week, migrate onto the ferns, and commence feeding. The larvae look like a small slug. They are wrinkled, 1/3 inch in length, and olive-green to gray with black heads and legs (Figure 3).

 

Figure3. Common Asparagus Beetle Larvae Feeding on Asparagus (Author–Raymond Cloyd, KSU)

Larvae feed for approximately two-weeks and then drop to the ground, burrow into the soil, and form a yellow pupa. After several weeks, adults emerge and start feeding. Common asparagus beetles overwinter underneath plant debris, loose bark, or hollow stems of old asparagus plants. The life cycle can be completed in eight-weeks. There are two generations in Kansas.

The adults and larvae feed on asparagus spears and can defoliate ferns if populations are extensive. Larvae consume leaves and tender buds near the tips, which leaves scars that eventually turn brown. Damage caused by larvae interferes with the plant’s ability to photosynthesize (manufacture food); thus depleting food reserves for next year’s crop.

The plant protection strategies that can be implemented to reduce problems with common asparagus beetle populations include: applying insecticides; hand-picking eggs, adults, and larvae and placing into a container with soapy water; and/or removing any plant debris after the growing season to eliminate overwintering sites for adults. Insecticides should be applied as soon as common asparagus beetles are present, and again in late summer through early fall to kill adults before they overwinter. Thorough coverage of all plant parts is important in suppressing populations.

 

 

 

Ant and Termite Swarms

— by Dr. Jeff Whitworth and Dr. Holly Davis

 

April is usually the month that most ant and/or termite swarms occur.  Thus, it is extremely important to distinguish between an ant and a termite.  Ant swarms have already been noted (5 April) this year with more to come. Both ants and termites are very common throughout Kansas although the damage potential and treatments costs are significantly different.  Therefore, proper identification is extremely important!

 

If the swarm is determined to be ants, the next question is whether they are carpenter ants.  Most of our ants are scavengers and therefore won’t really cause a problem, other than being a nuisance.  Carpenter ants are also scavengers; however, they do excavate and nest in soft woods including plywood, plasterboard, insulation, wood affected by water seepage, etc.  Unlike termites, they do not consume wood and wood products.  Carpenter ants range in size from ¼ inch to nearly 1 inch long and may be reddish to black in color, making them look very similar to many other ant species in Kansas.  For many, the easiest characteristic to positively identify carpenter ants is the tiny ring of hairs on the very end of the abdomen, which may require a hand lens to see.  Treatment for carpenter ants, as with most ants, is most effective by locating and treating the nest.

 

Showing red and black carpenter ants

For more information on ants, including carpenter ants, please see Ants, MF-2887: https://www.bookstore.ksre.ksu.edu/pubs/mf2887.pdf

 

Alfalfa Weevils

— by Dr. Jeff Whitworth and Dr. Holly Davis

Very small alfalfa weevil larvae were 1st detected on 5 April, 2019 in north central Kansas.  Every field sampled had at least one newly hatched larva.  There were not enough to sample for a treatment threshold as they are just hatching.  The 1st indication of these small larvae are visible, but very tiny, pinholes in leaves, or a little chewing on plant terminals.  These tiny larvae are quite difficult to dislodge from their feeding sites when they are this small.  Thus, sampling at this early stage to determine an infestation level is not practical using the bucket-shake method or a sweep net.

 

2019 Kansas Paraquat Training Information

–by Frannie Miller, Pesticide & IPM Coordinator

Frequently Asked Questions

So do all paraquat dichloride product labels require the additional training?

The Environmental Protection Agency is allowing the sale of paraquat that is already in the channels of trade, so some paraquat sold during this growing season may NOT require the new training requirement on the label. In the future all products featuring the new labeling with the active ingredient paraquat dichloride, such as Gramoxone, Firestorm, Helmquat and Parazone will require the additional training in order to apply these products. Remember if the new training requirement is listed on the label of the product you are using, then you MUST complete the training.

How often am I required to receive the training?

The training is required every three years.

Do I need to be certified to use products containing paraquat dichloride?

The newly labeled products state that “Product may ONLY be mixed, loaded or applied by a certified applicator who has successfully completed the paraquat-specific training before use. Application “under direct supervision” of a certified applicator is NO LONGER allowed. In the state of Kansas, this means that everyone purchasing and using these products has to either obtain a private applicator license (application to agricultural lands owned or operated by individual) or a commercial applicator license (applicators applying to other people’s land for compensation). If you have been applying under someone else’s license in the past you will need to get your own license before applying these products.

 

How can I complete the training requirements?

 

The only training that meets the requirements is housed on the eXtension website and can be found by going to: http://usparaquattraining.com. If you don’t currently have an account you will need to create one before it will allow you to take the training.

 

This information is made available by the K-State Pesticide Safety and IPM Program. Contact your local Extension Office if you need any additional information.

 

 

2019 Kansas Dicamba Training Information

–by Frannie Miller, Pesticide & IPM Coordinator

Frequently Asked Questions

 

Do all dicamba product labels require the additional training?

You are required to have additional label-required dicamba training when applying the restricted use dicamba products: Engenia, FeXapan, or XtendiMax.

Where can I get the training for 2019?

BASF:  (webinars, online training and face to face) https://www.engeniastewardship.com/#/training

Bayer/Monsanto: (online training and face-to-face) https://www.roundupreadyxtend.com/stewardship/education/Pages/default.aspx

Corteva: (online training)

https://www.corteva.us/products-and-solutions/crop-protection/fexapan.html

 

Do I need to attend training if I already did in 2018?

The labels of these products state that prior to applying this product in the 2019 growing season, all applicators must complete dicamba or auxin-specific training on an annual basis, so even if you attended in 2018 you will need to attend a training in 2019 prior to applying these products.

 

Do I need to be certified to use these products?

The new labels state that these formulations are for retail sale to and use only by certified applicators. In the state of Kansas, this means that everyone purchasing and using these products has to either obtain a private applicator license (application to agricultural lands owned or operated by individual) or a commercial applicator license (applicators applying to other people’s land for compensation). If you have been applying under someone else’s license in the past you will need to get your own license if you are applying these products.

 

My hired hand and I both hold private applicators licenses. He will be doing all my spraying. I am taking the dicamba training, but does he also have to take the dicamba training?

Yes, anyone who applies one the RUP dicamba products must complete an approved dicamba training and hold either a private or commercial applicator license.

 

Do other states accept Kansas’s state-approved RUP dicamba training?

Nebraska accepts all other states’ training so long as the applicator receives the Nebraska Department of Agriculture module with its state specific information. Oklahoma and Colorado will accept Kansas’s state approved training. This year Missouri does not have any state specific rules so they will be accepting the registrants training, but applicators need to note they apply in MO so the training can be turned into that state.

 

This information is made available by the K-State Pesticide Safety and IPM Program. Contact your local Extension Office if you need additional information.

 

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