BIOLOGY OF THE CORN LEAF APHID, RHOPALOSIPHUM MAIDIS (HOMOPTERA: APHIDIDAE), IN SOUTHWESTERN ONTARIO

Abstract

There was no evidence that the corn leaf aphid, Rhopalosiphum maidis (Fitch), can overwinter in southwestern Ontario. An alate with a small colony of nymphs was found on 26 April, indicating that migration from the south starts early in the spring. Early migrants colonized winter barley, but not winter oats, rye, or wheat. Colonization on field corn did not occur until over a month after plant emergence. Only small numbers of alatae initiated infestations on corn and the large variation in size of aphid infestations observed at pollination was due to differences in the longevity and fecundity of these few early attackers. The whorl leaves which enclosed the tassel before pollination provided a very favorable environment for rapid development of the aphids. Trapping of alatae in yellow pans of water at the periphery of a corn field in the fall showed that a minimum temperature of 13°C was required for flight. At a constant temperature of 25.5°C and a light:dark photoperiod of 14:10 h, the average prereproductive, reproductive, and postreproductive periods for 29 aphids were 5.9, 15.8, and 9.6 days, respectively. The average number of nymphs produced/female was 68.2.

Direct and indirect effects of warming on aphids, their predators, and ant mutualists

“…This allowed us to test whether the two ant species were functionally redundant in terms of their indirect effects on aphids. Corn leaf aphids (Rhopalosiphum maidis) are globally distributed agricultural pests that attack maize and other Gramineae species (El-Ibrashy et al 1972, Foott 1977, and are commonly found in Wisconsin, USA, cornfields. As sap-sucking herbivores, aphids feed exclusively on phloem, which is rich in carbohydrates but poor in 1 E-mail: btbarton@wisc.edu other nutrients like nitrogen (Gray and Fraenkel 1954).…”

Feeding Ecology of the Red-Winged Blackbird in Field Corn in Ontario

“…In our study, all the food items found in the collected blackbirds either were sampled in the cornfields where the birds were taken or were known to occur in cornfields (pers. observ., Everly 1938, Weekman 1962, Haynivik and Frye 1969, Foott 1977. Weed species that were consumed in small amounts by a few birds, but were not sampled in the 4 fields, may have been too rare, or too clumped to be detected in the sampling.…”

“…Aphid movement from the tassels to the corn leaves, stem, and ears typically peaks during mid to late August in southwestern Ontario (Foott 1977). Other animal food items (fly larvae and pupae, beetles, millipedes, centipedes, and ants) may have been eaten during ground searching by birds.…”

Influência da temperatura no desenvolvimento de Rhopalosiphum maidis (Fitch, 1856) (Hemiptera: Aphididae) em condições de laboratório

“…Chaudhary et al (1968) verificaram para R. maidis em trigo, a 19 o C, uma produção total de 34,2 ninfas, sendo inferior em cerca de 34% do total produzido a 18 o C neste trabalho. Foott (1977) observou uma produção total de 68,2 ninfas de R. maidis em milho, a 25,5 o C, assemelhando-se ao número de ninfas constatado a 24 o C neste experimento. Assim como para a produção diária, constatou-se a influência do tipo da planta e origem geográfica das espécies, além do fator temperatura, sobre a capacidade total de produção de ninfas de R. maidis.…”