Cane Dieback Research Articles

Infestation pattern of foliar nematode,Aphelenchoides ritzemabosi(Nematoda: Aphelenchoididae), on boysenberry

Abstract Infestation behaviour of the foliar nematode, Aphelenchoides ritzemabosi on boysenberry (Rugus strigosus) plants was studied in 2 commercial gardens at Motueka, South Island, New Zealand. Nematodes overwintered in the pruned stubs of old fruited canes, then invaded primocanes (new growth produced before winter) in early spring when plants broke dormancy, causing a brown streaking and epidermal peeling on stems. The nematode feeding site was directly beneath the cane epidermis, and conductive tissue remained protected by tough cork cambium. In well managed gardens infestation was restricted to the lower 1 m of the plant regardless of population density. Despite infestation, yields were high and no plant death, cane die-back, or bud death was noted. One garden had a disease symptomatic of crown gall, and a close association was found between the distribution of cane galling and nematode infestation within plants. Gall tissue yielded very high numbers of A. ritzemabosi. The behaviour of the nematode in relation to crop husbandry practices is considered in this paper and the need for cultural control methods is discussed.

Phytophthora citricola . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Phytophthora citricola . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Antirrhinum majus, Brachychiton populneum, Ceanothus sp., Citrus spp., Erica hiemalis, Hibiscus spp., Humulus lupulus, Lycopersicon esculentum, Malus pumila, Primula japonica, Rhododendron catawbiense, Ribes grossularia, Rosa sp., Rubus idaeus, Schinus moue and Syringa vulgaris . Also pathogenic on inoculation to: Chamaecyparis sp., Cupressus sp., Cydonia oblonga, Euphorbia resinifera, Lycopersicon esculentum, Malus pumila, Phaseolus vulgaris and Pinus sp. (Waterhouse, 1957; 39: 249; 40: 433; Herb. IMI.) DISEASES: Brown rot of oranges, black root of hops, root rot and cane die-back of raspberry, die-back of rhododendron and basal rot of tomato seedlings. GEOGRAPHICAL DISTRIBUTION: Africa (South Africa); Asia (Formosa), Australasia & Oceania (Australia, New Zealand); Europe (Great Britain, Germany, Italy (Sicily)); Central America & West Indies (Antilles); North America (U.S.A.); South America (Argentina). TRANSMISSION: Soil-borne. Survives as mycelium in host roots and as oospores in soil (45, 3381b). Also intercepted once in Czechoslovakia on oranges imported from Turkey (42: 197).