Researchers identify new pasture pest in Santa Catarina

Leandro do Prado Ribeiro, researcher and entomologist at the Research Center for Family Agriculture (Epagri/Cepaf), together with other researchers and technicians from Brazil and the United States, identified a new pest in Bermuda grass pastures in Santa Catarina. According to him, “impressive population outbreaks” of the leafhopper have been observed Metadelphax propinqua (Fieber) (Hemiptera: Delphaciae), a sucking pest species associated with several species of cultivated plants.

This was the first time that the association of the pest with Bermuda grass cultivars, one of the most used forage crops in Santa Catarina, was identified in Brazil. The discovery was reported in a study recently published in the journal Neotropical Entomology.  

The pest, found in January and February 2023 in hay production areas in Chapecó and other municipalities in the Western region, was initially analyzed at the Epagri/Cepaf Entomology Laboratory. Additional morphological and molecular analyzes were subsequently carried out, which confirmed the taxonomic identification of the species. These analyzes were collaborated by researchers Fábio Nascimento and Eduardo Gorayeb, from CAV/Udesc and professor Charles Bartlett, from the University of Delaware, in the United States. 

The Epagri researcher details that the infested plants showed leaf chlorosis, which is a yellowing or loss of color resulting from the leafhoppers feeding. A reduction in the growth rate of plants was also observed, due to sap sucking and injection of toxins, as well as the deposition of honeydew, a sugary secretion eliminated by leafhoppers during the feeding process. This secretion can lead to the development of sooty mold, a fungus of the genus capnodium responsible for reducing the photosynthetically active area of ​​the plant. “However, the biggest concern lies in the fact that this species is reported as a vector of important phytopathogens for Bermuda grass and other species of cultivated plants, including corn”, warns Leandro. 

"In literature, M. propinqua is reported as a vector of Cynodon chlorotic streak virus (CCSV) for bermudagrass, and maize rough dwarf virus (MRDV) and maize yellow striate virus (MYSV) for corn cultivation”, reports the entomologist. He also remembers that M. propinqua transmits the most economically important disease for corn in Argentina: Mal de Río Four virus (MRCV). Another interesting aspect observed by the researchers was that the phylogenetic diversity data conducted in the study showed a genetic similarity greater than 99% between populations collected in Santa Catarina and genetic sequences from samples from Argentina. 

According to Leandro, this is a pantropical species, that is, it is present in the tropical regions of all continents between latitudes 50° north and 40° south. Its habitat includes coastal areas and agricultural landscapes of southern and central Europe and hot temperate and tropical zones of all continents: Africa, Asia, Australia, Europe and North and South America.

The cigarette M. propinqua is a polyphagous species, which means that it feeds on diverse plants, typically associated with monocotyledons, including important cultivated species such as pastures, sugar cane, barley, corn and rice. “As it is a new species in Brazilian crops, we do not yet have tools for its management. However, monitoring the areas is essential to recognize the problem, its distribution throughout the Santa Catarina territory and also the impact on forage production systems here in the State”, highlights the researcher.