Invasive Species Compendium

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Abstract

Seasonal activity and control of rice root aphid, Rhopalosiphum rufiabdominalis (Sos) (Aphididae: Hemiptera) in upland paddy.

Abstract

A study on the seasonal activity of the rice root aphid (R. rufiabdominalis), its parasites and dispersing agents, as well as on the efficacy of insecticides against them, was undertaken in rice cv. Ngoba, sown in Barapani, Meghalaya, India. The insecticides tested were the granular carbofuran 3G, phorate 10G, diazinon 10G, aldicarb 10G and thiometon 5G, each at 1.0 kg/ha. Spray formulations of carbaryl 50 WP, BDC 50 WP, endosulfan 35 EC, malathion 50 EC, quinalphos 25 EC, dimethoate 30 EC, phosphamidon 85 EC, monocrotophos 36 EC, formothion 25 EC and thiometon 25 EC, each at 0.05%, were also given. The activity of rice root aphid was maximum in 1 May-sown paddy when 19 adults and 4.22 aphid colonies were recorded in 10 hills. The activities of its insect and nematode parasites, i.e. Aphelinus sp. and Hexamermis sp., respectively, increased progressively in different dates of sowings from April to June. However, in the case of 1 July-sown paddy, there was a decrease in the incidence of rice root aphid and its parasites. The activities of aphid dispersing agents, i.e. ants (Tetramorium bicarinatum, Pachycondyla sp. and Camponotus sp.) and termite (Pericapritermes sp.), were found maximum in 1 May to 1 June sowings and decreased in the latter sowings. The mite Uroobovella marginata was also found associated with the aphid and its dispersing agents in the rice root zone. It indicated that in early-sown paddy rice root aphid infestation remained low as a result of its poor initial population and comparatively low temperature in April. On the other hand, monsoon rains were responsible for the decreased activity of the dispersing agents in the latter sowings that affected adversely the dispersal of this aphid from hill to hill. The maximum rice yield was recorded in April-sown paddy under protected conditions. Among the 5 systemic insecticides, phosphamidon, monocrotophos, formothion and thiometon were found significantly superior in efficacy, whereas among the 5 contact insecticides, endosulfan only was found effective against this aphid. The safety of these insecticides to the parasite of rice root aphid was reflected in the yield of inside-grown upland paddy.