Corn and soybeans are flourishing during the critical pollination period. To protect yield potential, CHS agronomy experts recommend farmers regularly scout fields and apply crop protection products as needed.
Harvest is shaping up to be a good one, says Kurt Lahr, a CHS regional product specialist. He works with growers and retailers in Illinois, Wisconsin and parts of Minnesota and South Dakota.
“In my 17 years in this business, I’ve never seen a crop look this good over so many acres. We really need to protect it,” Lahr says.
According to the weekly U.S. Department of Agriculture Crop Progress Report, 74% of U.S. corn was in good or excellent condition on July 13, 10 percentage points better than the five-year average. On that date, 70% of soybeans were in good or excellent condition, the third best percentage in 25 years, according to the report.
Spring wheat is mostly headed out, with 54% in good or excellent condition, the report indicates, with the crop in North Dakota, South Dakota and Minnesota rated considerably better.
“An environment that benefits crops – plenty of moisture and heat – is also perfect for diseases and insects,” Lahr says. “Now is the time to be scouting.”
Watch for these five diseases and insects:
1. Tar spot
“Tar spot is a hot-button disease. It can be detrimental to corn yield,” Lahr says.
The pathogen first showed up in fields about 10 years ago. The fungus produces small (1/16 to 3/4 inch), round to irregular round and/or diamond-shaped, raised black structures called stromata. The pathogen can drastically reduce yield by limiting photosynthetic capacity of leaves and cause rapid, premature leaf deterioration and death.
Fungicides with two or three modes of action applied between the VT and R3 growth stages are most effective, according to a recent multi-state study published by the Crop Protection Network (CPN).
2. Southern rust
Southern rust is a fungal disease in corn that can reduce photosynthesis and, consequently, yield. The disease is typically troublesome for farmers in Texas and Oklahoma, says Eli Parr, a regional product specialist with CHS covering those states along with Kansas, Colorado and Nebraska.
“Farmers did a good job with proactive fungicide treatments to mostly keep the disease at bay this season. The corn looks really good with all the moisture,” Parr says. “Farmers need to keep scouting, though, and treat as needed.”
3. Corn rootworm beetles
Corn rootworms are a problem in some areas, Lahr says. To save money, some farmers opted to plant corn that lacked below-ground traits to combat the pest.
Rootworm eggs hatch in the spring and larvae feed on roots, making plants susceptible to lodging. The larvae pupate and turn into beetles, which emerge from the soil in the summer to feed on corn silks, pollen and leaves. Clipped silks can disrupt pollination and reduce yield.
“You can curb pressure by scouting to identify females and gauge numbers,” says Lahr. “If populations are above the threshold, spray an insecticide that can be included in a tank mix. Since surviving females lay eggs, it’s a problem that compounds if you don’t act.”
4. Soybean aphids
Soybean aphid populations fluctuate throughout the growing season, so it is important to scout on a regular basis to monitor populations.
Aphids can be found on any above-ground portion of the soybean plant, including leaves, stems and pods, according to Iowa State University Extension information. Aphid feeding can cut yield up to 40%, but this extreme yield loss usually only occurs when heavy infestations result in sooty mold development on leaves. Many foliar insecticides are highly effective.
5. White mold
White mold is a common, potentially detrimental soybean disease. The pathogen is more prevalent during wet, humid and cool seasons after the canopy closes during flowering and during early pod development, according to CPN.
“There has been plenty of moisture [to spur disease growth this summer],” Lahr says.
Early disease symptoms include water-soaked lesions on the main stem. As the disease progresses, the lesions appear bleached and encircle the stem. Leaves turn brown and the plant eventually dies. Foliar fungicides are most effective when applied immediately before infection, according to CPN.
Other yield-protecting tips
Lahr and Parr encourage farmers to consider other opportunities to boost and preserve yield.
“A lot of farmers are talking about adding supplemental nutrition along with crop protection products to boost yield and offset low prices,” says Lahr. “They know when the stars align, it’s not the time to pull back.” Bollbuilder®, a foliar-applied fertilizer for any food or fiber crop where the addition of calcium, boron, manganese and zinc would be beneficial, is an in-season nutrient option.
Adding an adjuvant, such as Petichor®, to crop-protection tank mixes is a great way to make the most from your investment, he adds. Petrichor is a drift management agent that will improve performance of herbicides, fungicides and insecticides by increasing canopy penetration and deposition, improving humectancy and maintaining uniform droplet size.
“I know a grower who tested Petrichor in a field with tar spot. On the acres he used the adjuvant, there was a 28-bushel increase compared to the acres without it.”
Find out more information on CHS adjuvants.
