b'Corn rootworm damages corn root systems by chewing and feeding on the young roots, which interferes with the plants ability to efficiently absorb water and nutrients.PHOTO: BAYER CROP SCIENCEThe Battle with Corn RootwormEradicating this pest can be tough, but there are practices corn producers can use to help manage yield loss caused by this insect.Lisa KopochinskiCORN ROOTWORM (CRW)isnt called the billion-dollarSafeer Hassan, corn systems manager at Bayer Crop Science pest for nothing. Unfortunately, it has earned this unsettlingin Greater St. Louis, Missouri, agrees and adds that root feeding moniker due to it being a devastating insect pest that costs U.S.damage may also lead to lodging, which can cause difficulties at growers over a billion dollars in crop losses and managementharvest. CRW is also capable of causing yield losses of up to 45%. practices annually.CRW pressure has also been on the rise for the past few Essentially, its larvae damages corn root systems by chewingyears and there are several factors responsible for this increased and feeding on the young roots, which interferes with the plantspressure. These included growing corn on the same field for ability to efficiently absorb water and nutrients.multiple years without rotation to a non-CRW host crop such as If feeding is severe, plants may lodge, making harvestsoybeans; favorable environmental conditions for larval survival; difficult, explains Tim OBrien, traits manager at Syngenta inand potential development of resistance to Bt traits.Downers Grove, Illinois.Once the larvae mature, they emerge from the soil as adultEradication Measuresbeetles to mate and lay eggs that will overwinter and hatch theWhen it comes eradicating this pest, Nick Tinsley, a technical following season. The adult beetles can also clip ear silks andfield representative at BASF who covers the Eastern Corn Belt, interfere with pollination. Populations of corn rootworm varysays there is little hope of eradicating corn rootworm altogether. by field based on past crop history, soil type and environmentalHowever, there are a number of practices that corn producers conditions. can use to help manage yield loss caused by this insect. Because Grain markets can be a contributing factor as stronger cornthe larvae feed nearly exclusively on corn roots, crop rotation can prices sometimes increases corn-on-corn acres. Mild wintersbe a great option for many growers. with insulating snow cover and lower moisture at larval hatch canIt should be noted, however, that many areas of the Corn Belt support an increase in survival leading to more larvae feeding onhave populations of corn rootworm that are able to counter this corn roots.practice through various adaptations, he explains. In general, environmental conditions in some areas of theMany seed- or soil-applied insecticides are labeled for corn Corn Belt supported increased CRW larval feeding in 2020rootworm and can be very effective for reducing yield loss. and 2021, with environmental conditions in 2022 leading to lessFinally, transgenic hybrids continue to offer significant value in larvae and feeding, explains OBrien. Butfrom Coloradoterms of protecting yield from corn rootworm. No matter the across the country to New York statethe crop history andtechnique used, growers should take time to evaluate the effec-past management are normally the leading factors projectingtiveness of their management program by digging and evaluating the CRW populations of a field. roots in mid-July.118/ SEEDWORLD.COMDECEMBER 2022'