Forecasting yield of corn, Zea mays infested with corn leaf aphid, Rhopalosiphum maidis

Abstract

Corn leaf aphid, Rhopalosiphum maidis (Fitch) is one of the most serious corn pests in Egypt. The aim of the present study is to assess the corn yield losses and to build forecasting models of yield related with aphid infestation. Number of aphids/plant were determined during corn growth stages 10 leaves (V10); tasseling (VT); ripening 2 (R2) and ripening 4 (R4). At the end of growing season, yield losses were estimated. Results revealed that infestation with aphids through V10-VT caused 28.14% yield losses at average aphid density 818 aphid/plant. Infestation through R2-R4 caused 16.28% yield losses at average aphid density 1038 aphids/plant. Percentages of yield losses of corn ears through V10-R4 were 14.66, 22.9, 35.28 and 36.03% at average aphid density of 100, 1000, 2000 and 3000 aphids/plant. As ear yield negatively correlated with aphid density, regression analysis was used to construct forecasting yield models. Statistical analysis showed that simple linear and logarithmic models provided a good fit to the data and also indicated that the two models are similar in prediction of ear yield. These constructed models were diagnostic checked using new data. The checking revealed that the linear model is stable and valid where insignificant difference was observed between predicted and actual yield.

The role of detoxifying enzymes in the resistance of the cowpea aphid (Aphis craccivora Koch) to thiamethoxam

“…Throughout the world, the cowpea aphid (Aphis craccivora Koch) is considered to be a serious insect pest to a variety of crops (Blackman and Eastop 2000;Al-Eryan and El-Tabbakh 2004;Kuo et al 2006). Aphids cause significant economic damage either directly; by sucking sap from leaves, pods, and other aerial tissues, or indirectly; through transmission of major viruses like the faba bean necrotic yellows virus (FBNYV), and the bean leaf roll virus (BLRV) (Laamari et al 2008).…”

Yield response of cowpea, Vigna unguiculata L. (Walp), to infestation of Aspavia armigera F. (Hem., Pentatomidae)

“…The knowledge of yield-loss relationships between a crop and its associated pests is an important aspect of any insect pest management programme (Hammond and Pedigo 1982). Such knowledge helps in establishing the economic status of a pest, finding the infestation level that justifies control (action threshold) and gives a basis for directing future research and agricultural planning (Al-Eryan and El-Tabbakh 2004). The information will also be useful in facilitating decision-making with regard to the adoption of suitable sustainable pest management strategies.…”

Performance of corn leaf aphid, Rhopalosiphum maidis (Fitch) (Homoptera: Aphididae) on selected maize hybrids under laboratory conditions

“…The corn leaf aphid, Rhopalosiphum maidis (Fitch) (Homoptera: Aphididae), is a serious pest of maize with Asiatic origin but it is now distributed throughout the tropics and temperate regions of the world (Hill, 1987;Blackman and Eastop, 2000;Al-Eryan and El-Tabbakh, 2004;Kuo et al, 2006). This aphid is a polyphagous pest and can cause damage to many host plants species and weeds from Gramineae and occasionally Cyperaceae and Typhaceae.…”