Healthy fields bring higher yields but may also serve as beacons for hungry insects. While the worst U.S. drought since 1956 caused pastures and crops to deteriorate, it also left fewer host plants and fall crop stubble for insects to feed on. Aphids, tiny insects that feed on infected host plants and crop stubble, can carry the devastating barley yellow dwarf virus (BYDV) to wheat planted this fall. With a few more weeks of winter wheat planting left, there is still potential for fall aphid pressure to creep up on growers. To reduce risk, it’s important for growers to be proactive and protect their crops from the start, enabling them to grow more wheat and achieve higher profits.
It all starts with an aphid
Although the 2012 drought may have decreased the potential for fall aphid pressure, it only takes one aphid to transmit BYDV to a field. There are multiple species of aphids, but only certain species transmit BYDV. Most common of the BYDV-transmitting aphids include the bird cherry-oat aphid, corn leaf aphid, English grain aphid and Greenbug.
Aphids contract BYDV by feeding on infected host plants, and then BYDV is spread as infected aphids feed on healthy plants. This virus can cause underdeveloped root systems, plant stunting, winterkill, decreased tillering, delayed maturity, nutritional disorders and reduced grain quality and yield.
Researchers have identified that the fall population of aphids has the greatest potential to vector BYDV and leads to the most dramatic decrease of yield in the spring. If growers are not proactive in ensuring their crops are protected this season, this tiny insect can have a devastating impact on yield by vectoring BYDV.
Be proactive: Postpone planting, eliminate the "green bridge" and scout fields
First and foremost, researchers and agronomists recommend delaying fall planting, eliminating the green bridge and diligently scouting fields.
With the drought this year, delaying planting until the later part of the planting window may allow for more moisture, and it can also help growers actively prevent aphid infestations. Later fall planting dates are recommended to give aphids less time to transmit the virus before cold temperatures set in.
Agronomists also suggest eliminating the green bridge by controlling green residue in the field. This residue will act as a “bridge,” connecting infected aphids to the new crops and allowing for the spread of BYDV.
Les Glasgow, herbicide technical asset lead, Syngenta, recommends growers destroy green residue with a burndown application of herbicide at least two weeks before planting begins.
Get an insurance policy
Prevention is key with BYDV. Scouting aphids in the fall is a difficult and lengthy process, and by the time aphids are spotted in a field, it’s likely the infection is present already, too. A grower’s best option is to prevent aphids from attacking in the first place with a quality insecticide that provides a defense against BYDV.
“You don’t know for sure if you are going to have an aphid or BYDV problem before the planting season. But, you do know that if you apply a seed treatment, you are virtually eliminating the risk,” said Jim Swart, extension specialist, Texas AgriLife Extension. “Seed treatments help ensure you don’t end up with BYDV. In effect, it is basically an insurance policy.”
Like any good insurance policy, Cruiser offers full protection from yield-robbing insects from the moment seeds are planted, working systemically to protect plants as they grow. Even if there is little or no aphid pressure this fall, thiamethoxam, the active ingredient in Cruiser, has been proven to produce healthier, more vigorous plants. This phenomenon is called the Cruiser Vigor effect, and it has been seen on a variety of crops, resulting in faster emergence, improved plant stands, increased root mass, thicker stems, earlier canopies, taller and greener plants, improved quality and higher yield potential. Ultimately, Cruiser helps growers maximize productivity and increase their bottom lines.
Protect in the spring, too
Fall aphid attacks may be the most devastating, but aphids can cause significant damage in the spring, too. As the year goes on and spring emerges, growers should continue to be proactive against aphids with diligent scouting. If aphids are present, a foliar application of insecticide may be warranted. It can help prevent crop damage from spring aphid attacks. Check with your state or local extension office for aphid threshold level spraying recommendations in your area.
While the drought of 2012 may be keeping aphids at bay for now, fall conditions can change quickly into those favored by this yield-robber. At the start of the season, invest time to protect your crops by delaying planting, eliminating the green bridge and scouting fields. Continue to scout in the spring as the weather warms up, as aphids can cause major damage at this point, too. If necessary, apply a foliar insecticide for control. Ultimately, an integrated approach that includes scouting, sound management practices and quality seed treatments and crop protection products will help ensure a healthy, pest-free crop with maximum yield potential.