1. Field Observations and Weather Outlook

Corn crops are looking great. Whether they were planted toward the beginning of May or more toward the middle of the month, I'm seeing good ear development. This is especially encouraging since many fields planted toward the middle of May or later were substantially shorter than what we'd expect. But they've definitely made a comeback.

Soybeans are also looking good and are at or near canopy closure. I've seen a few foliar diseases in some crops that were more stressed (nodulation issues), so hopefully those with the opportunity were able to make fungicide applications when they had the chance.

The next 7-10 days looks like a washout for many of us, so while hay crops will have to wait, this is very welcome news for ear development and pod fill. But with good moisture comes the risk of foliar diseases. While the time for action may have passed for most of us, monitor diseases in your crops so you can make good management decisions next year. Rotation is always the best medicine, but for those acres that won't be rotated, make sure you can manage next year whatever might be developing and building inoculum now.

Remember: Silage corn needs 750-800 GDD (depending on hybrid maturity) after silking to reach a whole plant DM of 32%. Under typical late season dry down conditions we can expect the crop to reach 35% DM four to seven days later. We can expect to accumulate 20-25 GDD per day, or even up to 30, so peak maturity can creep up on us quickly. But no matter what the numbers say, always check your crop to see how close you may be to harvest. For more details, see this article.

2. Growing Degree Days (GDD) (See: Climate Smart Farming Growing Degree Day Calculator)

Growing degree days (GDD) are calculated by taking the average daily temperature and subtracting the base temperature for development of a given organism ((High + Low)/2 - base temp = GDD). For corn silage, we are using base 50/86, as corn development starts at 50 degrees F and ceases above 86. Check your location and planting date:

3. Pest Monitoring

Table 1. Potato leafhopper scouting: PLH numbers remained low this week, and the rain should help suppress PLH until harvest.

Table 2. Corn moth trap data

We're currently in the peak flight period of Western bean cutworm (WBCW), but trap numbers below 100/week suggest that finding a notable infestation in the adjacent field is unlikely. Even capture rates above 1000/week don't necessarily indicate that a damaging infestation is likely. Over the years we've been fortunate to have relatively low populations of WBCW in our region, and hopefully they remain that way. Viptera Bt hybrids are effective at protecting crops against this pest.