Presence of <I>Dalbulus maidis</I> (Hemiptera: Cicadellidae) and of <I>Spiroplasma kunkelii</I> in the Temperate Region of Argentina

Abstract

"Corn stunt" is one of the main corn (Zea mays L.) diseases in the Americas and Dalbulus maidis (DeLong & Wolcott) is the key vector of the pathogen Spiroplasma kunkelii Whitcomb. In Argentina, the corn-producing area is in the temperate region, where vector and pathogen prevalence levels are unknown. In this study, the prevalence and distribution of D. maidis and S. kunkelii in the temperate region of Argentina and D. maidis overwintering ability in this region were determined. Surveys were conducted in 2005-2006 and 2006-2007 seasons to determine D. maidis and S. kunkelii presence, and in winter 2006 to determine the vector overwintering ability. The highest S. kunkelii prevalence and incidence levels were found in the transition area from the temperate to the subtropical region, related to the highest D. maidis prevalence and insects sampled per location. D. maidis adults were found in volunteer corn plants and spontaneous vegetation in autumn and winter months, which were inoculative for the pathogen S. kunkelii. This overwintering ability was related to detection of D. maidis insects in corn crops at early growth stages in the following growing season. This work emphasizes that corn stunt disease is present in the temperate region of Argentina, and this highlights the need to develop proper agronomic practices like monitoring insect vector populations and controlling voluntary plants. This study also indicates that further research is needed to understand the potential yield reduction caused by this pathogen on symptomless plants and population dynamics of the insect vector.

Characterization of components of resistance to Corn Stunt disease

“…Corn Stunt disease was first confirmed in the subtropical region of Argentina during the 1990/ 91 crop season [9]. High disease prevalence was later reported in this region in 1996/97, 2001/ 02, 2006/07 and 2010/11 crop seasons [7,8,10], and isolated symptomatic plants may be found occasionally in temperate areas of Argentina [8,[11][12][13].…”

Effects of temperature on the development, performance and fitness of the corn leafhopperDalbulus maidis(DeLong) (Hemiptera: Cicadellidae): implications on its distribution under climate change

“…Moreover, at 15 °C, egg development was observed until the appearance of eye spots, although there was no hatching as host plants failed. Considering that the vector can develop at higher or equal temperatures of 17 °C, its ability to spread into temperate zones as reported by Carloni et al () is not unusual.…”

Corn Stunt Disease: An Ideal Insect–Microbial–Plant Pathosystem for Comprehensive Studies of Vector-Borne Plant Diseases of Corn

“…Corn pathogens transmitted by D. maidis have been reported in all corn-growing regions where the insect is present and have caused damage, ranging from 40%–100% yield loss. Limited scientific information is available regarding the targets and mechanisms of resistance in corn against Spiroplasma infections [ 67 ]. For this reason, it is important to understand the components of the corn stunt disease.…”