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Extension Entomology

Category: Sunflower

Grasshoppers

–by Jeff Whitworth — Field Crops

As noted before, grasshoppers seem to be really numerous this year throughout northcentral Kansas. We have seen, or heard about, more grasshopper-riddled fields (see pic 1) then we have maybe in the last 15-20 years. The species responsible for most of the crop damage is the common, relatively large, yellow, differential grasshopper (see pic 2). These grasshoppers are still feeding a little, but are also moving to grassy/weedy/undisturbed areas where they are depositing eggs in the soil. These eggs will then hatch next spring and the young nymphs can start feeding on any nearby crops.

Picture 1: Grasshopper riddled field (pic by Cayden Wyckoff)

Picture 2: Differential grasshopper (pic by Cayden Wyckoff)

 

 

Beneficial’s

–by Dr. Jeff Whitworth — Field Crops

Beneficial’s continue to be very active throughout all crop fields in the eastern half of Kansas (please see fig 4–pink spotted lady beetle depositing eggs, 15 July). Thus, the practice of just adding an insecticide into any tank mix with fungicides and /or herbicides “just in case” is NOT recommended. Please ensure any targeted pest meets, or is close to, a treatment threshold before utilizing an insecticide application.

Figure 4. Pink Spotted Lady Beetle depositing eggs (pic by Kaysie Morris)

Soldier Beetles

–by Dr. Jeff Whitworth

Have had several inquiries regarding soldier beetles (please see fig 3 provided by Kaysie Morris). These beetles are quite common throughout Kansas and most commonly noticed in late summer as the adults are highly mobile, relatively large, and are very active searching for and feeding on pollen. Thus, they can be very common on any crop, or weed, that is pollinating, especially sunflowers, sorghum, and cucurbits such as cantaloupes and watermelons. Soldier beetles are often mistaken for blister beetles because of their size and shape but are not in the same taxonomic family and thus, produce no cantharidin, the chemical that causes external blisters in humans and other problems in livestock when ingested. However, soldier beetles are harmless.

Figure 3 soldier beetle

 

Sunflower Update – Gray and Red Seed Weevils

–by Dr. Jeff Whitworth and Dr. Holly Schwarting

Double-cropped sunflowers are highly susceptible to both gray and red sunflower seed weevils.  Most double-cropped sunflowers sampled in the past week, just reaching the bud stage, were significantly infested with both seed weevils, i.e. more than two of each species/plant.

 

 

 

These weevils are, and will be ovipositing and the small grub-like larvae will consume or otherwise destroy the seed.  This damage can significantly reduce yield if enough seeds are destroyed.  For more information on sunflower insect pest management, please refer to the KSU Sunflower Insect Management Guide: https://www.bookstore.ksre.ksu.edu/pubs/mf814.pdf