University of Missouri Extension Upcoming Meetings

Wednesday, August 9, 2017

Missouri Rice Field Day†- August 24, 2017, Rice Research Farm Hwy J, west of Malden

Fisher Delta Research Center Field Day - August 31, 2017, Rone Hall, Portageville

Corn Meeting - December 13, 2017 at the Miner Convention Center, Miner, MO

Soybean Meeting - January 17, 2018 at the Miner Convention Center, Miner, MO (Date Updated)

Meet University of Missouri President

Meet MU System President Mun Choi for his presentation and a question and answer session on Thursday, August 10 at 5:30 PM at the MU Cape County Extension Center at 684 West Jackson Trail in Jackson, Mo.

Corn Disease Update

Southern rust was confirmed this week by the MU Plant diagnostic lab for a sample from Cape Girardeau County. Much of the corn in the area is R4 (dough) to R5 (dent) this week which puts the corn past the critical time period of R1 (silk) to R3 (milk), where research indicates that fungicide applications are warranted. Cooler weather in the forecast plus dry weather for most the area will slow the advancement of the disease to some degree. I have included a link on corn rusts.

One other corn question that I received a call about this week is the potential for aflatoxin this year. Aspergillus ear rot may produce the mycotoxin known as aflatoxin. Aspergillus is a mold that favors hot, dry weather conditions and is typically associated with drought stress. If these conditions continue through ear development then the mold growth can increase. This season has been a mixed bag of wet followed by dry and hot. I donít know if conditions overall have been favorable for elevated levels of ear rot. However, management considerations would include harvesting and drying. Setting combines to avoid excessive kernel damage and fan speeds to remove lighter infected kernels are two harvest practices. Aflatoxin will occur on grain in the field, but much more will develop in wet, warm corn stored on a truck or in a grain tank for a few days. The fungus grows best when 18% moisture corn is stored at 86 degrees F. To help avoid this problem, avoid storing corn on a truck or in a bin for any length of time. Ideally, dry it to 15% moisture within 24 hours of harvest. If you intend to store grain for an extended period, dry it down to at least 12-13% moisture to inhibit further aflatoxin development.

Soybean Pest Management

Late season pests have begun to emerge this past week. Stink bugs are one best to begin scouting for as soybeans begin to move into later reproduction stages. Stink bug thresholds are an average of 9 stink bugs per 25 sweeps when using a sweep net or 1 stink bug per foot of row using a drop cloth. Another pest to continue to monitor is corn earworm (podworm) which has thresholds of 9 larvae per 25 sweeps or more than 1 per foot of row and pod damage. Kudzu bug has been identified in an isolated area of Dunklin county but this is another potential pest to be on the lookout for in 2017. I have included a link on kudzu bug from Dr. Scott Stewart, UT Crops page.

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