Aphid

About: Aphid is a research topic. Over the lifetime, 11380 publications have been published within this topic receiving 229721 citations. The topic is also known as: Aphidoidea & plant lice.

Trichomes of Lycopersicon spp. and their effect on Myzus persicae (Sulzer) (Hemiptera: Aphididae)

Abstract: The green peach aphid (Myzus persicae) is becoming resistant to many of the pesticides used in the tomato (Lycopersicon esculentum) industry A potential alternative method of control is host-plant resistance, which may be mediated by trichomes Resistance to the green peach aphid was assessed for six accessions of L hirsutum, three of L pennellii and a L esculentum control Mortality, entrapment and number of aphids unaffected by trichomes were recorded 24, 48 and 72 h after placement Using multiple regression against counts of glandular and non-glandular trichomes, the role of foliar pubescence in resistance to the aphid was established Lycopersicon pennellii possessed the highest level of resistance after 72 h and type IV trichome density accounted for 265% of variance in mortality (P < 0001) Low densities of type IV and high densities of type VII trichomes increased the number of aphids ‘unaffected’ by trichomes, a relationship accounting for 29% of variance (P < 0001) Information on which types of trichomes most strongly affect resistance to insect pests will aid future breeding and L pennellii shows potential for use in breeding programs to increase levels of host-plant resistance in L esculentum

Intraguild predators and the spatial distribution of a parasitoid

Abstract: An experimental plot of the aphid Aphis fabae on various host plant species was colonized by natural populations of the aphidiine parasitoid Lysiphlebus fabarum and insect predators, especially coccinellids. Parasitism of A. fabae by L. fabarum was significantly depressed on plants bearing coccinellids. The number of parasitized aphids increased with aphid abundance on three plant species (Papaver dubium, Rumex obtusifolius, Vicia faba), but not on the plant species (Chenopodium album) which bore very high numbers of coccinellids. In complementary laboratory experiments, L. fabarum offered a choice between odours of plants infested with A. fabae and/or coccinellids selected the odour fields from coccinellid treatments at significantly lower frequency than the odour fields of other treatments. It is concluded that avoidance of coccinellids by L. fabarum contributes to the negative association between the abundance of coccinellids and parasitoids in the field.

Natural Enemies of Russian Wheat Aphid (Homoptera: Aphididae) and Associated Cereal Aphid Species in Spring-Planted Wheat and Barley in Colorado

Abstract: Colorado has experienced high levels of Russian wheat aphid, Diuraphis noxia (Kurdjumov), damage and is considered an important site for release of biocontrol agents. In June 1990, field surveys were initiated to provide baseline data on the identity and prevalence of existing aphid pathogens, parasites, and predators. Sampling was conducted in spring-planted grain in irrigated and dry-land fields near Fort Collins and Akron. D. noxia was the most abundant aphid; populations were high in both irrigated and dry-land fields. Parasite prevalence was low <5%) in all fields. D. noxia was the most frequently parasitized aphid, and the most common parasite was Diaeretiella rapae (M'Intosh). Syrphid fly larvae were the only predators consistently found feeding on aphids within the D. noxia –damaged (rolled) leaves. However, syrphid populations were low, <0.3 larvae per aphid-infested tiller. The ineffectiveness of the existing complex of parasites and predators in suppressing D. noxia populations underscores the need for introductions of more efficient biocontrol agents. Pathogenic fungi were active in nearly all fields; three species were found. In irrigated fields, Entomophthora chromaphidis Burger & Swain was the most common pathogen during the spring, with peak prevalence of 13% on 22 June. Pandora (= Erynia ) neoaphidis (Remaudiere & Hennebert) was not detected until late June, but it rapidly reached epizootic levels (44% infection by 18 July). Highest prevalence (20%) of Conidiobolus obscurus (Hall & Dunn) coincided with that of P. neoaphidis . Prevalence of fungal pathogens in dry-land fields did not exceed 2.5%. The observation of only low levels of entomophthoralean fungal infection in the nonirrigated fields suggests that reliable use of these natural control agents against aphids in the semiarid West will require manipulation of environmental conditions through irrigation.

Performance of Lipaphis erysimi (Homoptera: Aphididae) on different Brassica species in a tropical environment

Abstract: A 2-year study on the preference and performance of Lipaphis erysimi on different Brassica species in the field and under greenhouse conditions revealed that rapeseed (B. campestris var. BSH-1, B. campestris var. YSPB-9) and mustard (B. juncea RH-30) were better hosts for this aphid than other Brassica species (B. napus, B. nigra, Eruca sativa, B. carinata). On the first group of plants, the rate of nymphal development, longevity and fecundity of this pest were significantly less than on the second group of plants. Development was significantly prolonged when the aphid was reared on second group of plants.