Spittlebug damage on tropical grass and its impact in pasture-based beef production systems

Guilhermo Francklin Souza Congio,Tiago Alves Corrêa Carvalho Da Silva,Diogo Fleury Azevedo Costa,Moacyr Corsi,Pedro Castro De Almeida,Tadeu Ruzza Barreto,Vitor Afonso Tinazo

doi:10.1038/s41598-020-67490-9

Abstract

Spittlebugs are the main pest of tropical pastures and Marandu palisade grass (Urochloa brizantha cv. Marandu) is the most representative cultivated pasture in the tropics. Our objective was to characterize Marandu palisade grass responses subjected to Mahanarva (Hemiptera: Cercopidae) attack and to estimate the losses in terms of beef production from pasture-based systems. A set of five experiments were carried out. Three consecutive years of monitoring showed that Mahanarva spittlebugs increased their abundance after first rains with three to four peaks throughout the wet season. A decrease of 66% on herbage yield was observed in the greenhouse trial, with an average decrease of 61% on pools of calcium, magnesium, phosphorus, sulfur, potassium, crude protein, neutral-detergent fiber and in vitro digestible dry matter of Marandu palisade grass. Results from field experiments corroborated with greenhouse trial showing decreases on herbage yield varying from 31 to 43% depending on level of fertilization and grazing severity of Marandu palisade grass. Finally, an unprecedented 154-ha field experiment indicated that Mahanarva decreases 74% the beef productivity (i.e. kg body weight ha−1) of Nellore heifers grazing Marandu palisade grass.

Highlights

Spittlebugs are the main pest of tropical pastures and Marandu palisade grass
Our results showed that spittlebugs of the Mahanarva genus can strongly affect Marandu palisade grass physiology
These studies were conducted during four-month period mimicking a long-term infestation similar to what would occur during the wet season on field, whilst our greenhouse trial lasted only 20 days

Summary

Introduction

Spittlebugs are the main pest of tropical pastures and Marandu palisade grass Our objective was to characterize Marandu palisade grass responses subjected to Mahanarva (Hemiptera: Cercopidae) attack and to estimate the losses in terms of beef production from pasture-based systems. Results from field experiments corroborated with greenhouse trial showing decreases on herbage yield varying from 31 to 43% depending on level of fertilization and grazing severity of Marandu palisade grass. Rich.) Stapf]} is the most representative of the cultivated pasture species, grown in about 50 million hectares in the c ountry[8] It was launched by Embrapa in 1984 as an alternative to signal grass From the mid-1990s, spittlebugs from the genus Mahanarva have been reported infesting several species of Brazilian tropical pastures, including Marandu palisade g rass[10,11]. The number of generations may vary from 3 to 4 depending on the wet season duration[10,22]

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