Brazil: New rules for thiamethoxam recommend drip irrigation in sugarcane

The Brazilian federal environmental regulatory agency, Ibama, has restricted the use of insecticides containing the active ingredient, thiamethoxam, on various crops, due to its impact on pollinating insects.

However, agronomic specialist Dávilla Alves from Netafim said that these new guidelines recommend drip irrigation as a safe approach for sugarcane. Ibama's decision prohibits the non-directed application of the insecticide through aerial spraying and agricultural tractor spraying. The understanding behind this evaluation process is that both methods can cause issues affecting the role of bees and other pollinating insects in the ecosystem due to drift, Alves added. 

Thiamethoxam is an active ingredient in neonicotinoid insecticides that has been registered and widely used for controlling polyphagous pests, such as whiteflies, stink bugs, leafhoppers, and aphids. In Brazil, the new measures impose restrictions on certain forms of its use, such as the non-directed foliar application of the active ingredient on crops, including eucalyptus, tomato, and grape, Alves further added.

On the other hand, its use will be permitted on crops such as corn, wheat, soybeans, and sugarcane, for directed application on the soil or leaves, as well as a seed treatment, with new conditions, such as doses and deadlines, to be further specified. 

For sugarcane, the ingredient is used to control root froghopper (Mahanarva fimbriolata), termites (Heterotermes tenuis), sugarcane borer (Diatraea saccharalis), sugarcane weevil (Sphenophorus levis), and sugarcane stalk borer (Euetheola humilis) during the crop cycle. ″With the new rules, the industrial treatment of vegetative propagules has been suspended,″ Alves further said. 

However, under Ibama's decision, the product's use on sugarcane via the soil through directed application is still allowed. Ibama recommends the safe application of the substance on sugarcane through drip irrigation, as there is no risk of drift exposure.

″Therefore, if soil applications are necessary on ratoon cane after harvest, a 35 to 50-day interval between the first application should be followed to avoid contact between pollinators and the exudate,″ Alves explained, noting that regarding the efficiency of application and control of target pests using thiamethoxam via the drip irrigation system, Netafim aims to find answers through trials for controlling root froghoppers.

″The results obtained in commercial sugarcane production fields, conducted at sugar mills and sugarcane producers, demonstrate a significant reduction in the insect similar to the foliar application of the product while maintaining sugarcane vigor, meaning that control efficiency remains similar compared with the treatment being sprayed,″ she added.

″The practice of using drip irrigation is a sustainable and effective technique in phytosanitary management, as it facilitates the application of pesticides for pest and disease control with greater precision during product application, and ensures better operational safety,″ she added.

″In addition to environmental safety for beneficial insects, the system ensures operational safety, as there is no contact between field workers and the spray solution, allowing for reduced labor or even their reallocation to other activities,″ Alves said in conclusion.

(Editing by Leonardo Gottems, reporter for AgroPages)