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Within‐field spatial distribution patterns of corn planthopper, P eregrinus maidis , and severity of hopperburn and M aize mosaic virus symptoms as influenced by sunn hemp intercropping
Author(s) -
Manandhar Roshan,
Wright Mark G.
Publication year - 2016
Publication title -
entomologia experimentalis et applicata
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.765
H-Index - 83
eISSN - 1570-7458
pISSN - 0013-8703
DOI - 10.1111/eea.12498
Subject(s) - intercropping , biology , planthopper , monoculture , population , spatial distribution , field trial , agronomy , population density , ecology , mathematics , statistics , medicine , environmental health , hemiptera
Habitat management (e.g., intercropping) may alter within‐field spatial distribution patterns of herbivores, from a typical pattern as observed in a monoculture, and may influence patterns of crop injury. Field trials were conducted to study the effect of intercropping maize, Z ea mays L . ( P oaceae), with sunn hemp, C rotalaria juncea L . ( F abaceae) strips on within‐field spatial distribution patterns of corn planthopper, P eregrinus maidis ( A shmead) ( H emiptera: D elphacidae), and combined severity of hopperburn and M aize mosaic virus ( MMV ) ( R habdoviridae: N ucleorhabdovirus) symptoms. In each field trial, spatially explicit data on P . maidis counts and ratings of severity of symptoms were obtained by sampling maize plants at weekly intervals. These data were used to examine the spatial patterns of P . maidis and severity of symptoms in maize‐intercropped and monoculture plots with Spatial Analysis for Distance IndicEs ( SADIE ) methodology. Spatial aggregation patterns of P . maidis in each treatment plot were not consistent among the field trials and tended to be mediated by their population densities. Interpolation of local cluster indices showed that P . maidis were more often aggregated at the field edges, irrespective of treatment. At times of MMV incidence in field trials (fall 2010 and spring 2011), the patch clusters of P . maidis and symptomatic plants were located at the field edges, but were spatially unassociated in both treatment plots. The results provided an approximation of the unpredictability of P . maidis spatial patterns at different population densities and their association with severity of symptoms in two maize‐cropping systems. However, the gap clusters of symptomatic plants were primarily located at the field interiors and were larger in intercropped than in monoculture plots. Such spatial pattern of symptomatic plants resulted in the reduced incidence of MMV in the intercropped plot compared with the monoculture plot, suggesting intercropping sunn hemp can be a useful tool in the management of MMV in maize fields.