After the heavy infestations of western flower thrips about 6 weeks ago, spider mite infestations in corn have been hard to find. But, spider mites seem to be recovering. In my field trials near Hart, Tx spider mites were beginning to build in some of my plots. The infestations were increasing in some plots, but not in all plots, next to the field edges. And spider mites were also increasing in other plots that were further out into the field. The mite predator densities per leaf were very low, < 0.5 predator / leaf. The primary predator found was the six spotted thrips adults and larvae.
John Quillin sent me this photograph yesterday of spider mites. So, be on the look out for hot spots of spider mites. They could be found throughout the fields.
|Photo: Mr. John Quillin|
Moth Trapping Activity
Southwestern Corn Borer (SWCB)
Deaf Smith county had a very noticeable increase in SWCB moth activity in two out of 4 location across the county (See SWCB graph). Last week there was an average of 10.5 SWCB moths per trap compared to this week’s collection of 54, 80, 206, and 347 moths per trap. None of the other counties saw this type of increase of SWCB moths. The other counties had less than 10 SWCB moths per trap. These moth trap collections in Deaf Smith county are still low compared to previous years when peak collections have been in the hundreds or thousands. These increases are an indication we are beginning the second generation SWCB moth flight.
Fall Armyworm (FAW)
Again Deaf Smith county, along with Dallam and Randall counties, had fall armyworm moths trap catches ranging from a low of 31 at a location to a high of 160 at another location. All other FAW trap numbers for the other reported locations were < 20.
Western Bean Cutworm (WBC)
The western bean cutworm moth numbers ranged between 6 to 53 moths per trap, with the mean at 33 WBC moths per trap. The counties reporting these numbers were from Dallam, Hartley, Moore to Hutchinson and down to Deaf Smith and Randall counties. These numbers are 1/8th to 1/4 the numbers we have trapped in other years. Although the numbers are low, we still need to be diligently looking for egg masses and larvae.