Population Dynamics of Dichelops melacanthus (Dallas) (Heteroptera: Pentatomidae) on Host Plants

Abstract

The stink bug Dichelops melacanthus (Dallas) has become one of the major pests of corn and wheat in Brasil, mainly after a shift from the conventional tillage system to the no tillage cultivation system. This fact may be due to the simultaneous occurrence of second planting corn with wheat cultivation, and the presence of wild hosts. This study aimed to evaluate the population dynamics of D. melacanthus on wild hosts adjacent to areas cultivated with corn, wheat, and soybean during the season and off-season of soybean cultivation. Weekly surveys were conducted in the region of Londrina, PR, Brasil from the beginning of July 2007 up to the end of June 2008 using the square meter method. Corn (Zea mays), soybean (Glycine max), tropical spiderwort (Commelina benghalensis), hairy indigo (Indigofera hirsuta), crotalaria (Crotalaria pallida), wheat (Triticum aestivum), and signal grass (Brachiaria decumbens) were identified as hosts of D. melacanthus. Signal grass was the host in which stink bug adults were found in higher numbers, while nymphs and adults were consistently collected on tropical spiderwort. Although nymphs completed their development on tropical spiderwort seeds, this host was found less suitable than soybean seeds.

Tratamento de sementes para manejo do percevejo-barriga-verde na cultura de soja e milho em sucessão

“…É importante destacar que as densidades populacionais observadas se aproximam de níveis observados em outros trabalhos, como os de Carvalho (2007) e Silva et al (2013). Estes autores observaram pico populacional do percevejo em abril, com densidade de aproximadamente 4,1 e 3,0 insetos por metro quadrado, em Ponta Porã, MS, e Londrina, PR, respectivamente.…”

“…Os dados de flutuação populacional indicam que, apesar de ter ocorrido baixa densidade populacional de percevejos em soja, essa cultura pode ter contribuído para a incidência do inseto em milho cultivado em sucessão. Particularmente, na safra II, a densidade populacional de D. melacanthus começou a aumentar a partir do final do ciclo da soja e, em milho, atingiu níveis cerca de 3,2 vezes maior em comparação à safra I. Segundo Chocorosqui & Panizzi (2008), Silva et al (2013) e Smaniotto & Panizzi (2015), a soja possibilita o desenvolvimento completo, a reprodução e o aumento populacional de D. melacanthus, o que não ocorre em milho. Assim, na sucessão soja-milho, a soja pode contribuir para o desenvolvimento da população de percevejos que ocorrerá em milho cultivado em seguida.…”

Damage caused by Dichelops melacanthus (Heteroptera: pentatomidae) in conventional and transgenic corn hybrids

“…Silva et al (2013) found that adult D. melacanthus migrate to cornfields looking for shelter and water sources, and can be harmful to plants. Ávila and Panizzi (1995) found that the occurrence of D. melacanthus is greater during the plant's vegetative phase, and its population density decreases near the reproductive period.…”

Characterization of antixenosis toDichelops melacanthus(Hemiptera: Pentatomidae) in soybean genotypes

“…As the plant cycle comes to an end, the plants become less attractive and provide inadequate food and other resources for insect breeding, encouraging dispersion toward late genotypes and/or alternative hosts such as dayflowers [Commelina benghalensis (L.)] or Indigofera spp. (Silva, Ventura et al 2013;Smaniotto & Panizzi 2015). The bugs feed directly from the seeds, causing damage to soybeans from the beginning of pod formation until the end of grain filling.…”