Seed treatment can generate up to 90% efficiency in controlling leafhoppers at the beginning of the corn cycle

Corn cultivation continues to face one of the main phytosanitary challenges in its history, stunting, which can reduce grain production in susceptible plants by more than 70%, according to information from Embrapa. In addition to ensuring that the area is free of volunteer corn plants (tiguera or guaxas), another method that can help reduce the incidence of the problem is seed treatment, which helps protect the corn plant until it emerges and earn your first leaves.

According to Bayer's corn crop specialist, Paulo Garollo, treating the seeds is a crucial management practice to keep adult leafhoppers (Dalbulus Maidis), the insect vector and disseminator of the stunt complex, away from the newly established corn crop. “This management can bring an efficiency of up to 90% at the beginning of sowing, this significantly reduces the incidence of the pest in the crop, in addition to facilitating management against it later on. In other words, it is another preventative care that will help prevent the problem from getting out of control”, he comments.

One of the seed treatments that has shown greater efficiency and good results in the field is the chemical group of neonicotinoids, comments Garollo, which not only help with the management of leafhoppers, but also another difficult-to-control pest, the green-bellied stink bug.

“The first tip for the producer is to observe whether the seed treatment purchased is registered for the target pest, in this case the leafhopper, with the specific dose for it. Some commercial products recommend higher doses for leafhoppers, in relation to bedbugs, for example.”

Industrial treatment

When purchasing seeds, the producer has the option to choose whether the seeds will be delivered with industrial treatment (TSI) or the coating will be applied on the farm itself. According to Garollo, although the costs seem lower when the option is to do it yourself, several factors show that this is not worth it.

“The treatment carried out with industrial machines ensures that each seed receives the exact amount of the active ingredient, homogeneously and with greater adherence. In the treatment carried out on the farm, the producer will have to divide the time that already takes place during sowing to carry out the process and will not be able to dedicate himself as he should. Furthermore, the active ingredient is placed in the mixing tank and there is no guarantee that each seed will receive the right amount of it, being capable of generating imperfections that can compromise the individual protection of the plants, in addition to increasing the chance of blocking distribution. of the planter”, comments the specialist in corn cultivation.

Industrial treatment also prevents seeds that are out of standard size from being passed on to the producer and that specific machinery does not cause cracks or cracks during the application of active ingredients. On the farm, management is more rustic, normally carried out in tanks that can cause damage to the seed.

“If, after treatment on the farm, the seed has a fissure or crack, there is a high chance of this causing diseases during the emergence period, or even facilitating the entry of fungi that cause the death of plants before they even emerge. In other words, the savings generated in treatment will bring losses due to this uneven and flawed farming”, comments Garollo. “This is an unnecessary headache, as the cost-benefit is not worth it.”

Storage care

Once the treatment method has been defined, another point of attention that can drastically change the effectiveness of this strategy is seed storage. According to the Bayer specialist, the producer needs to be aware of the agreed moment of receiving the seed and that it is appropriate to the corn planting start calendar, so as not to extend the storage time for this seed.

“A treated seed stored for a long time can lose its physiological quality and thus have its germination potential and vigor reduced. Of course, the storage location must also be suitable, the space cannot be too hot and stuffy. The ideal is to choose to store them on pallets, to ensure good air circulation and less moisture capture from the soil, as well as avoid placing them close to fertilizer or salt for animal feed, which capture moisture that can be transmitted to the plants. seeds,” says Garollo.

If the producer has already started planting and has to interrupt work, mainly due to rain, it is important that the seeds stored in the planter's tanks do not come into contact with moisture.

“Keeping the seeds in the planter tanks overnight is not a problem. However, this machinery needs to be kept out of the rain, stored in a shed, or even under a tarpaulin so that the seeds do not come into contact with moisture. If they come into contact with moisture, in addition to having a good chance of starting to germinate, they can swell, get stuck in the disc and ruin the planting”, comments Garollo.

Integrated management and monitoring

Garollo highlights that seed treatment alone is not sufficient to minimize the level of incidence and damage caused by the leafhopper. The Integrated Pest and Disease Management (MIPD) also includes the choice of more tolerant hybrids, the elimination of voluntary corn and the recurring monitoring of areas. This is because not every farmer plants on the same date and, as leafhoppers are capable of moving great distances per day (over 20 km in one day), the population explosion can happen even from one day to the next, so It is important to be aware and act before losing control.

“Having taken all these initial precautions, producers must remain alert and continue monitoring their areas. And, when noticing that the leafhopper population is increasing, opt for chemical control, completing the actions to minimize the damage caused by the stunting complex. Each of these management actions complement each other and reduce the leafhopper population, increasing the chance of success”, concludes the specialist.