to understand the relationship between natural physicochemical properties of soil and abundance of citrus root nematode (tylenchulus semipenetrans), a survey was conducted during 2009-2010 in some 37 citrus orchards, in kohgilouyeh va boyerahmad province, iran. distribution of the citrus nematode was determined by collecting random samples from the soil and citrus plant roots, extracting and en...

Burrowing nematodes from Central America, Dominican Republic, Florida, Guadeloupe, Hawaii, and Puerto Rico were characterized for their ability to parasitize citrus, but citrus parasites were found only in Florida. Sequence tag sites originally amplified from a citrus-parasitic burrowing nematode were polymorphic among 37 burrowing nematode isolates and were not correlated with citrus parasitis...

Seedlings of the hybrid citrus rootstock, Carrizo citrange (Citrus sinensis x Poncirus trifoliata) do not uniformly limit development of the citrus burrowing nematode, Radopholus citrophilus. Variation in nematode population densities in roots of seedlings germinating from the same seed suggests that factors responsible for nematode incompatibility are not functional or are not inherited unifor...

A Tylenchulus sp. found in a Georgia peach orchard parasitized peach roots in the greenhouse. Citrus roots were not parasitized, indicating that the nematode was not the citrus nematode. Morphologically similar populations were found in one peach orchard in Alabama, two orchards in Arkansas, and one in South Carolina. Males were present in the Alabama populations and one of the Arkansas populat...

Four biotypes (pathotypes) of the citrus nematode, Tylenchulus semipenetrans, occurring in California, U.S.A. were differentiated on the basis of differences of infectivity on 'Homosassa' sweet orange, 'Troyer' citrange, 'Pomeroy' and 'Rubidoux' Poncirus trifoliata, 'Thompson Seedless' grape, and 'Manzanillo' olive. A method for differentiating biotypes of T. semipenetrans is described. Field o...

1. Indirect plant defences are well documented for the above-ground constituents of plants. Although less investigated to date, below-ground defences that mediate multitrophic interactions are equally important. Entomopathogenic nematodes (Steinernema diaprepesi) are attracted to herbivore-induced volatiles from Swingle var. (Citrus paradisi · Poncirus trifoliata) when fed upon by root weevil,D...

Of the many nematode species that parasitize citrus, Tylenchulus semipenetrans is the most important on a worldwide basis. Management of the citrus nematode remains problematic as no one tactic gives adequate control of the nematode. An overall management strategy must include such components as site selection, use of non-infected nursery stock, use of at lease one post-plant nematode control t...

Metalaxyl significantly reduced population of Pratylenchus coffeae, Radopholus similis, and Tylenchulus semipenetrans in roots of Citrus limon (rough lemon) under greenhouse conditions. Postinoculation treatment of rough lemon seedlings was not as effective i n reducing nematode populations as was treatment before inoculation. Fewer nematodes infected metalaxyl-treated roots than nontreated roo...

Foliar sprays of 4 microg/ml oxamyl on sweet orange trees in a greenhouse slightly depressed the number of Tylenchulus semipenetrans larvae obtained from roots and soil, but similar treatments were not effective in two orchards. Soil drench treatments decreased the number of citrus nematode larvae obtained from roots or soil of citrus plants grown itt a greenhouse and in orchards. Exposure to 5...

Citrus rootstocks which significantly limited the reproduction of Tylenchulus semipenetrans (Cobb) "Citrus" and "Poncirus" biotypes responded to infection by producing a hypersensitive-type response in the root hypodermis, wound periderm and/or cavities in the root cortex, and/or abnormal vacuoles in nurse cell cytoplasm. Rootstocks which limited nematode reproduction also had significantly few...