Survival strategies of D albulus maidis during maize off‐season in B razil

• Published in: Entomologia experimentalis et applicata Vol. 147; no. 2; pp. 141 - 153
• Main Authors: Oliveira, Charles M., Lopes, João R.S., Nault, Lowell R.
• Format: Journal Article
• Language: English
• Published: 01-05-2013
• ISSN: 0013-8703; 1570-7458
• DOI: 10.1111/eea.12059

Abstract
Despite the importance of
D
albulus maidis
(DeLong & Wolcott) (
H
emiptera:
C
icadellidae) as a vector of maize‐stunting pathogens, it is not understood how this leafhopper survives the maize off‐season in regions where overwintering hosts do not occur. We investigated migration and the use of alternate hosts as possible survival mechanisms for
D
. maidis
during maize off‐season in
B
razil.
D
albulus maidis
populations were monitored with yellow sticky cards for 16–29 months in
A
nastácio (Mato Grosso do Sul State), in two farms with perennial pastures (Pasture1 and Pasture2), where maize had not been planted for >5 years, in a subsistence farm >20 km distant, where maize was annually planted (spring) (Maize1), and in
P
iracicaba (
S
ão
P
aulo State), where maize was grown year round (Maize2).
RAPD
‐
PCR
analysis of leafhoppers sampled on maize in two plots (Maize1 and Pasture1) at 15–20 and 110–120 days after germination was performed.
D
albulus maidis
was trapped in the maize plots of all areas, but not in weedy or woody vegetation adjacent to the plots. Higher numbers were trapped throughout the year in
P
iracicaba, where maize was continuously grown under irrigation, and in the subsistence farm of
A
nastácio, where volunteer maize plants were available for long periods in the maize off‐season. In
A
nastácio farms, some population peaks were recorded in the absence of maize from midwinter to early spring, especially after soil plowing.
RAPD
‐
PCR
analysis showed that
D
. maidis
populations sampled were genetically similar. Our data suggest that
D
. maidis
uses a mixed strategy to survive the over‐season period in
B
razil, in which part of the population overwinters locally on volunteer maize plants or nearby irrigated maize crops, whereas the other individuals migrate to colonize new maize crops in distant areas or regions. We hypothesize that immigrant
D
. maidis
uses the contrast between plowed and vegetated soil as a visual cue for locating new maize crops.