Detection: Good pesticides for mulberry trees but for silkworms

Brazilian scientists have discovered the harmful effects of fungicides and pesticides used in agriculture on the yield and quality of the mulberry industry.

According to the Journal of Economic Entomology, an important issue when using pesticides in agriculture is their impact on organisms that have nothing to do with the use of pesticides . The negative impact of many chemicals on honey bees has been widely known. Brazilian scientists have recently determined that silkworm worms are also affected by agricultural pesticides.

Pyraclostrobin (a strobilurin fungicide) is good for mulberry trees but is harmful to silkworms - (Photo: Wikimedia Commons).

The original research purpose of Professor Daniel Nicodemo at the University of São Paulo is to determine if the pyraclostrobin (a fungicide belonging to the strobilurin group) will help improve the quality of silk. The use of this substance inhibits the growth of mulberry leaf disease, slows the aging of leaves and enhances the ability to withstand oxidation. Early experiments have confirmed that pyraclostrobin improves leaf nutritional value, but the results obtained when leaf-feeding worms are not as expected by scientists.

Pyraclostrobin acts on caterpillars similar to its effect on pathogenic fungi. Pyraclostrobin disrupts the operation of electron transport respiration chains, inhibits electron transport in mitochondria and reduces the production of energy-carrying molecules. Professor Daniel Nicodemo explains that pyraclostrobin acts as a respiratory chain inhibitor, affecting mitochondrial biology. Therefore, the expected major effect on mushrooms also occurs in silkworms. The consequence is an increase in the mortality rate of silkworm worms up to 3 times and a reduction in weight of cocoons produced by surviving silkworms.

Researchers do not rule out that other pesticides are also harmful to silkworms. Owners of the Brazilian silkworm farm have begun to realize that the yield and quality of silk deteriorates even when the worm is properly cared for and with adequate nutrition.

Because in Brazil the mulberry plantation area is often a small area surrounded by large plantations that grow corn, soybeans or sugarcane, where pesticides are used a lot, researchers believe that the chemicals used in agriculture is the cause of a decline in the quality and quality of silk.