Corn leafhopper: Epagri publishes updated monitoring for SC

The Monitora Milho SC Program released a bulletin with the first 15 weeks of monitoring the incidence of corn leafhopper and its infectivity for the 2023/2024 harvest. The report brings together data collected between July 24th and November 6th. In it, technicians and producers can check the number of leafhoppers captured per week in monitored crops in different regions of Santa Catarina. Monitoring also shows the infectivity of leafhoppers with stunting pathogens.

The corn leafhopper can be responsible for losses of up to 100% in crops. It is the insect vector of microorganisms that cause stunt complex diseases, which have been a major concern for Brazilian farmers in recent years.

Corn leafhopper monitoring

The majority of corn crops in Santa Catarina are at the end of the vegetative period, already entering the reproductive period, when the ear forms. Some producers are on the verge of harvesting for silage. “It can be seen that, from week 8 onwards, many crops had few insects (tables in green). This occurred due to the chemical management adopted by the producer”, explains researcher Maria Cristina Canale, from the Epagri Family Farming Research Center (Cepaf).

In Palmitos, in the Far West of Santa Catarina, there were five weeks in which the incidence of the leafhopper was low. “In this location, there are generally high incidences of leafhoppers. The difference between this property was the association of biological control with chemical control of insects”, explains the researcher. Cristina adds that, from October onwards, a lot of rain has occurred in the State, which may be indirectly impacting the natural control of the insect in crops, due to the intensification of the action of fungi that infect the leafhoppers.

Insect infectivity

Regarding infectivity, most of the insects captured are being diagnosed with the red stunt phytoplasma, in the crops monitored in Águas de Chapecó, Caxambu do Sul and Palmitos (West Santa Catarina), and in Major Vieira (Planalto Norte). “Spiroplasma has not been found frequently. Insect management in the initial stages may have contributed to the drop in infectivity in weeks 5 to 8 of monitoring, which correspond to part of the critical period of crop infection”, says Cristina.

Be careful with volunteer corn

The researcher reinforces that leafhopper management cannot be neglected during the implementation of the crop, up to the V8 stage. “Right now, the farmer must eliminate the tiguera (volunteer) corn that is developing in other crops, such as soybeans. These plants serve as “voluntary” maintenance of stunt pathogens and shelter from leafhoppers, and will serve as inoculum for the off-season corn, which is generally sown in the second half of December, until January”, he explains.

The Monitora Milho SC program is an initiative of the Action Committee against Corn Leafhopper and Associated Pathogens. This committee includes members from Epagri, Udesc, Cidasc, Ocesc, Fetaesc, Faesc, CropLife Brasil and the State Secretariat for Agriculture.

Leafhopper monitoring application

To help the production chain in monitoring and controlling the corn leafhopper in Santa Catarina, Epagri developed the Monitora Milho SC application. This app, available for free download, allows producers and technicians to monitor the incidence of corn leafhoppers to make more accurate management decisions. The tool also provides information on the infectivity of the leafhopper with the pathogens of the stunt complex: red stunt phytoplasma, pale stunt spiroplasma and stripe virus.

Epagri's recommendation is that producers and technicians maintain a routine for monitoring the application's data, because the insect's infectivity status can change from one week to the next. To find out how to manage the corn leafhopper, the producer should contact Epagri in his municipality or the Research Center for Family Agriculture (Epagri/Cepaf).