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Wheat Seedgall Nematode Anguina tritici. Etymology & Historical. Common name Wheat seed gall nematode Anguina tritici anguinos = snake-like tritici = host crop First PPN to be recorded by Needham in 1743 Steinbuch 1799 described it as Vibrio tritici
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Wheat Seedgall Nematode Anguina tritici Walia CCSHAU
Etymology & Historical • Common name • Wheat seed gall nematode • Anguina tritici • anguinos = snake-like • tritici = host crop • First PPN to be recorded by Needham in 1743 • Steinbuch 1799 described it as Vibrio tritici • Filipjev 1936 gave it the name Anguina tritici • In India, first reported by Milne 1919 from Punjab Walia CCSHAU
Systematic Position Walia CCSHAU
Diagnostic characters • Female • Adult female obese in the middle, 2.64-4.36 mm long; body coiled when heat relaxed; spear weak; 8-10 µm long with small knobs; oesophagus with a lobed basal bulb; ovary single with one or two flexures, anteriorly extending up to basal bulb, oocytes arranged in multiple rows about a rachis; vulva posterior; tail elongated conoid. • Male • Shorter than females, 2.04-2.4 mm long, more straight than females; bursa not covering the tail completely,; spicules short and broad. Walia CCSHAU
Adult female Walia CCSHAU
Anterior end - Female Walia CCSHAU
Distribution and Hosts • Distribution • Once present in all wheat growing regions of the world including Europe, Asia, USA, Australia, New Zealand, Russian states • Problem in India, eastern Europe and middle east. • India – Northern wheat growing states • Bihar, UP, MP, Rajasthan, Haryana, Punjab, Delhi • Hosts • Specific to wheat • Different species of Anguina form galls on different plant parts Walia CCSHAU
Biology and Life cycle • Parasite of above-ground parts • Source of infection – seed material contaminated with cockles • Each seed gall (cockle) contains 3000-12000 J2 in quiescent stage • Gain moisture in soil, become active and come out into soil • Ascend the growing point of germinating seedlings • Feed ectoparasitically between leaf sheaths and growing point till earhead emergence • Carried up along the growing plant, shielded among young leaves surrounding growing point • Enter floral primordia when earhead still inside boot leaf, become endoparasite • Earheads emerge, nematodes moult quickly to adults inside green galls • Each gall may contain several adults, mate inside, females lay eggs, fecundity high • Eggs hatch into J2, and become quiescent inside the gall as the crop matures • Only one life cycle in a season • Can survive inside a dried gall for 32 years Walia CCSHAU
Symptoms • Name of the disease – Gegla, Sehun, Mamni, Earcockle • Above-ground symptoms • Basal swelling of stem at 20-25 days • Crinkling, curling and twisting of leaves • Stunting and prostrate growth of the crop • Increased tillering • Earhead formation preponed • Affected earheads are shorter and broader • Glumes arranged loosely • Galls replace the seeds Walia CCSHAU
Basal Swelling; Crinkling, Curling of leaves Walia CCSHAU
Healthy v/s Diseased earheads Walia CCSHAU
Contents of a green gall Walia CCSHAU
Ruptured green gall Walia CCSHAU
Symptoms on earheads at maturity Walia CCSHAU
Cockles and Grains Walia CCSHAU
Cockles and Grains Walia CCSHAU
Contents of a mature cockle Walia CCSHAU
Interaction with other pathogens • Anguinatritici+ Clavibactertritici= Tundudisease or Yellow ear rot, Tannan • Nematode acts as vector • Initial symptoms same • Low temperature and High humidity favour disease • Yellow slimy ooze on leaves, stem, earheads • Upon maturity, turns brown • No grain formation • Earheads may not emerge from boot leaf • Tundu is more damaging than earcockle Walia CCSHAU
Tundu symptoms Walia CCSHAU
Tundu Walia CCSHAU
Losses • Seed contamination Loss in Yield 2.5 % 30% 6.5% 54% 8.5% 69% Incidence in Haryana Eacockle 2.3 – 8.2% Tundu 2.3 – 8.2% Organoleptic tests At 5% or > contamination in grains, significant deterioration in colour, texture, smell and taste of chapaties Walia CCSHAU
Control • Separation of cockles from seed • Dry cleaning • Winnowing/Fanning • Plain Water or Salt water (10-20%) floatation • Seed galls float on surface, seeds sink • Skim off the galls and destroy them • Use of certified seed • Possible to eradicate both diseases easily Walia CCSHAU