First detection of "Dalbulus maidis" in Oklahoma raises concern

The discovery of Dalbulus maidis, the corn leafhopper, in Oklahoma, United States, is a concern for farmers in the region. The insect can cause direct damage to corn and transmit pathogens. Prior to 2024, this pest had not been recorded in the state. There are warnings of the possible spread of the pest to other areas of the US Corn Belt.

Dalbulus maidis is native to Mexico. It has spread to other US states, such as California, Florida and Texas. In the case of Oklahoma, the presence of the insect was confirmed by the research team at the state university. Samples were collected from several commercial and experimental plantations, confirming the infestation in different counties. Identification was carried out using morphological and molecular techniques.

One of the major concerns regarding the presence of D. maidis is your ability to transmit Spiroplasma kunkelii, a bacterium associated with corn stunt disease. In the first Oklahoma field where the insect was detected, the infestation was severe.

According to scientists, the corn planting cycle in Oklahoma contributes to the permanence of D. maidis for much of the year. The state has several cultivation phases, including full-cycle and second-harvest plantations. These factors increase the availability of reproductive material for the leafhopper.

Studies indicate that D. maidis can survive without corn for up to nine weeks, as long as water is available. In addition, the insect has demonstrated the ability to survive the winter in moderately cold temperatures. This increases the risk that the pest will be able to establish itself permanently in the state. With climate change, the first frost on crops is occurring later, allowing for a greater period of reproduction and damage.

Another challenge faced by Oklahoma farmers is the limited use of effective pesticides. In Brazil, for example, products such as methomyl, carbosulfan and acephate are used to combat D. maidis. However, these pesticides are subject to restrictions in the United States, the researchers explain. Carbosulfan is not registered in the country. And the use of acephate is not permitted on corn crops. Thus, Oklahoma producers may face difficulties in controlling the pest. Especially considering that studies indicate that other active ingredients, such as pyrethroids and neonicotinoids, are less effective.

More information can be found at doi.org/10.3390/insects15100778