Author: John Obermeyer Several caterpillars in the ear can be very similar in appearance and habits, so identification to species of some of the worms in ears can be tricky. Note that, in general, you cannot use overall body color or damage for identification. Some identification tips, though not foolproof, appear below for the corn earworm, western bean cutworm, fall armyworm and European corn borer. We suggest you inspect cornfields soon before the larvae leave the ear and pupate.
Author: John Obermeyer In mid-June, we wrote in the Pest&Crop about the second surge of armyworm moths and suggested that dense, lush grasses (e.g., pasture) could be at risk. Though our pheromone trapping for armyworm ended at that time, Thomas Richards, NEPAC research farm (Whitley County), decided to continue monitoring out of curiosity. The mid-June moth count was 1674, the following week’s counts were 959,2009,1613, then beginning to tail off at 528 a month later. Those were some high counts! While driving a county road early this week, a very weedy field caught my attention. In stopping, I could finally tell that the field was planted into corn. In rows were spindles of stalks among the very heavy grass and broadleaf pressure. Entering the field, I didn’t find any active armyworm larva, though the telltale signs of their leaf feeding were present. There were fresh wheel tracks in the field[Read More…]
Author: Bob Nielsen “Scuttlebutt”: The cask of drinking water on ships was called a scuttlebutt and since sailors exchanged gossip when they gathered at the scuttlebutt for a drink of water, scuttlebutt became U.S. Navy slang for gossip or rumors. A butt was a wooden cask, which held water or other liquids; to scuttle is to drill a hole, as for tapping a cask. Nautical Terms and Phrases, NAVAL HISTORICAL CENTER, Washington DC 20374-5060. Online at www.ussbrainedd630.com/terms.htm [URL accessed Aug 2017]. The post-pollination scuttlebutt overheard in coffee shops throughout Indiana during late summer often revolves around the potential for severe stress that might reduce kernel set or kernel size in neighborhood cornfields. Growers’ interest in this topic obviously lies with the fact that the number of kernels per ear is a rather important component of total grain yield per acre for corn. Poor kernel set, meaning an unacceptably low kernel[Read More…]
Author: Bob Nielsen The grain fill period begins with successful pollination and initiation of kernel development, and ends approximately 60 days later when the kernels are physiologically mature. During grain fill, the developing kernels are the primary sink for concurrent photosynthate produced by the corn plant. What this means is that the photosynthate demands of the developing kernels will take precedence over that of much of the rest of the plant. In essence, the plant will do all it can to “pump” dry matter into the kernels, sometimes at the expense of the health and maintenance of other plant parts including the roots and lower stalk. A stress-free grain fill period can maximize the yield potential of a crop, while severe stress during grain fill can cause kernel abortion or lightweight grain and encourage the development of stalk rot. The health of the upper leaf canopy is particularly important for[Read More…]
Author: Bob Nielsen The other day, one of the patrons of Rudy’s Bar and Grill walks in with an ear of corn that exhibited long, flowing locks of blonde silks tumbling down the sides of the husk leaves and asked two questions: “Why are the silks so long?” and “Do such long silks bode ill for the success of corn pollination?” Well, maybe the 2nd question was couched in more earthy terms, but you get the drift. Both questions suggest that the guy has some experience thinking about sex in a corn field and understands that silks are the functional stigmas of the female flowers of a corn plant. Each silk connects to an individual ovule (potential kernel) and must be pollinated in order for fertilization of the ovule to occur and a kernel develop. The guy also seems to know that emerged silks are typically only 2 to 3[Read More…]
Authors: Joe Ikley and Bill Johnson Many people have commented that we have the best stands of corn and soybean across the state that we have seen in many years. Our dry planting window certainly helped get crops uniformly established, but now we have been receiving many questions about herbicide carryover injury on crops this year. Any discussion about herbicide carryover will focus on three key components: environmental conditions since herbicide application; chemistry of the herbicides applied; and interactions between the herbicide and soil conditions. Weather is usually the driving component whenever we see injury from a wide variety of herbicides applied the previous year. While we have not been as dry as areas in the western corn belt, a look at our total precipitation from August 1st 2017 until June 1st of this year shows a large area of the state had 4 to 6 fewer inches of precipitation[Read More…]
Authors: Joe Ikley and Bill Johnson After a delayed start to our planting season, we were able to plant both corn and soybean across the state in record or near-record time during May. This coincided with our hottest May on record, which was also dry in many areas of the state. This has allowed crops to emerge out of the ground quickly and rapidly progress through growth stages. We already have reports of waist high corn and flowering soybeans across the state. This article serves as a reminder for growth stage, height restrictions, and pre-harvest interval cutoffs for herbicide applications in both crops. Corn. There are a number of corn fields that did not receive a preemergence herbicide before the crops emerged from the ground. Many of these preemergence herbicides can also be applied postemergence. Some of the earliest cutoff timings are 8-inch corn for broadcast applications of 2,4-D, and[Read More…]
Authors: John Obermeyer and Christian Krupke Increasingly, slugs are becoming a topic of discussion with field crop producers. Not from the slugs’ disagreeable nature, but because damage to crops is becoming more apparent. Fortunately, we know enough about slug biology to better predict high-risk fields, namely those with high residues and minimal tillage. Unfortunately, we have very few management options, i.e., rescue treatment, once they become problematic. The best slug management tactic is done right now, simply to wait to plant when the soils are ready. This is being written on May 2, as producers throughout the state are in a rush to catch up on planting progress, especially with rain in the forecast. Slugs feed on all portions of the corn and soybean plant. Generally, foliage feeding, though unsightly, will not hinder yield. Because slugs are nocturnal, their perfect world is for easy entrance into the seed slot to[Read More…]
Author: Bob Nielsen The number of 30-, 40-, and 60-ft wide (or larger) field crop planters across the U.S. Midwest is greater today than, say, twenty years ago. Certainly, individual farmers can plant more acres of corn and soybean per day with today’s large field equipment than they could twenty years ago. This fact encourages optimism that planting season delays can be overcome by the capability of today’s modern planters to plant a greater percent of the state’s crop per week when “push comes to shove.” As is often the case with “logical conclusions”, the historical data do not necessarily support the logic. Historical planting progress data suggest that the maximum number of acres of corn and soybean planted per week has not changed much over the past 20 years. The accompanying figures illustrate the number of acres and percent of total acres planted during the respective weeks of maximum[Read More…]
The cost of seed corn is the largest single variable input cost for most Indiana corn growers (Dobbins et al., 2017). Minimizing that cost involves a combination of shrewd purchasing skills and wise selection of seeding rates. This summary focuses on our recent research evaluating the yield response of corn to plant population in field scale trials conducted around the state of Indiana.
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