Effect of newer insecticides against maize aphid, Rhopalosiphum maidis (Fitch)

Abstract The properties of maize pollen in the diet of Doru luteipes were determined by biological responses of the predator feeding on natural preys and artificial diet. The biological parameters of D. luteipes fed on Spodoptera frugiperda (Smith, 1797) eggs, maize pollen, Rhopalosiphum maidis (Fitch, 1856) + maize pollen and R. maidis were assessed. The effect of pollen on artificial diet on the biological variables of the predator nymphs and adults were also evaluated. Time span of nymphal development was greater for D. luteipes exclusively fed on earwigs, with the lowest rate of nymph survival. However, maize pollen plus earwigs in the diet provided the predator´s highest survival rate, whilst percentage of fertile females was double when fed on diets composed of S. frugiperda and R. maidis eggs. Development period decreased when D. luteipes nymphs consumed artificial diet plus pollen but there were high fecundity rates (number of laying/female and total egg/female) and a greater percentage of fertile females when they were fed on maize pollen.

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A Recently Discovered Maize Polerovirus Causes Leaf Reddening Symptoms in Several Maize Genotypes and is Transmitted by Both the Corn Leaf Aphid (Rhopalosiphum maidis) and the Bird Cherry-Oat Aphid (Rhopalosiphum padi)

Plant Disease ◽

10.1094/pdis-09-19-2054-sc ◽

2020 ◽

Vol 104 (6) ◽

pp. 1589-1592

Author(s):

Lucy R. Stewart ◽

Jane Todd ◽

Kristen Willie ◽

Deogracious Massawe ◽

Nitika Khatri

Keyword(s):

Infectious Clone ◽

Rhopalosiphum Padi ◽

Yellow Mosaic Virus ◽

Insect Vector ◽

Rhopalosiphum Maidis ◽

Maize Genotypes ◽

Chlorotic Mottle Virus ◽

Maize Chlorotic Mottle Virus ◽

Chlorotic Mottle ◽

Yellow Dwarf Virus

A maize-infecting polerovirus variously named maize yellow dwarf virus RMV2 (MYDV-RMV2) and maize yellow mosaic virus (MaYMV) has been discovered and previously described in East Africa, Asia, and South America. It was identified in virus surveys in these locations instigated by outbreaks of maize lethal necrosis (MLN), known to be caused by coinfections of unrelated maize chlorotic mottle virus (MCMV) and any of several maize-infecting potyviruses, and was often found in coinfections with MLN viruses. Although sequenced in many locations globally and named for symptoms of related or coinfecting viruses, and with an infectious clone reported that experimentally infects Nicotiana benthamiana, rudimentary biological characterization of MaYMV in maize, including insect vector(s) and symptoms in single infections, has not been reported until now. We report isolation from other viruses and leaf tip reddening symptoms in several maize genotypes, along with transmission by two aphids, Rhopalosiphum padi and Rhopalosiphum maidis. This is important information distinguishing this virus and demonstrating that in single infections it causes symptoms distinct from those of potyviruses or MCMV in maize, and identification of vectors provides an important framework for determination of potential disease impact and management.

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