Phenology and behaviour of the clearwing moth, Monopetalotaxis candescens (Lepidoptera: Sesiidae), associated with cultivated rooibos, Aspalathus linearis (Fabaceae), in South Africa

Production of 'rooibos' or red bush tea from Aspalathus linearis (Burman f.) Dahlgren (Fabaceae) is unique within the greater Cederberg region, Western Cape Province, South Africa. One of the principal insect pests associated with A. linearis production is the root-boring clearwing moth, Monopetalotaxis candescens Felder & Felder (Lepidoptera: Sesiidae). Annual moth flights peak during November/December, resulting in young plantations being targeted during the hot, dry summer conditions prevailing at this time. Average infestation levels progressively increased from 28 ± 2 % in year 1, to 53 ± 2 % and 72 ± 1 % in years 2 and 3, respectively. A second, 4-6 years old plantation during the three-year survey period was found to be severely infested (average 92 ± 1 %) with virtually no additional infestation over time. Estimated losses to borer infestation were calculated at 4, 24, 27 and 36 % in plantations that were 1-4 years old, respectively. Significantly more eggs were laid on leaves (66 ± 4 %) compared to woody tissue, stems and twigs. Most eggs hatched between 02:00 and 04:00, with neonates migrating down to the stem base and entering the root just below the soil surface. A control strategy, exploiting aspects of neonate migratory and feeding behaviour, should result in both yield increases and prolonged survival of plantations beyond the typical 4-5-year cycle.Articl

Natural occurrence of entomophthoroid fungi (Entomophthoromycota) of aphids (Hemiptera: Aphididae) on cereal crops in Argentina

The spectrum of entomophthoroid fungal species parasitising aphids on cereal crops and a study of the phenology and prevalence of these pathogens were investigated in Argentina. The studies were conducted at six different sites cultivated with crops of Triticum aestivum (wheat), Avena sativa (oats) and Sorghum bicolor (sorghum) during two consecutive years. Entomopathogenic fungi from the new phylum Entomophthoromycota were recorded from six aphid species on cereals in Argentina: Rhopalosiphum maidis, Rhopalosiphum padi, Rhopalosiphum rufiabdominalis, Schizaphis graminum, Sitobion avenae and Sipha maydis. Three species of entomophthoroid fungi were found infecting these aphid species: Pandora neoaphidis, Zoophthora radicans (Entomophthorales: Entomophthoraceae) and Neozygites fresenii (Neozygitales: Neozygitaceae). Entomophthoroid fungal infections occurred mostly in autumn–winter seasons (March–August), and coincided with periods of high relative humidity and comparatively low temperatures. This study represents the first base‐line characterisation of entomophthoroid fungi infecting aphids on cereal crops in Argentina.EEA RafaelaFil: Manfrino, Romina Guadalupe. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Área Investigación Agronomía. Protección Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Hatting, J. L.. South African Agricultural Research Council. Small Grain Institute; SudáfricaFil: Humber, Richard. United States Department Of Agriculture. Agricultural Research Service. Robert W. Holley Center for Agriculture and Health; Estados UnidosFil: Salto, Cesar Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Área Investigación Agronomía. Protección Vegetal; Argentina; ArgentinaFil: Lopez Lastra, Claudia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Estudios Parasitológicos y de Vectores; Argentin