Beet curly top virus (BCTV) is a single-stranded DNA virus in the genus Curtovirus (family Geminiviridae) with a very wide host range, including sugar beet, tomato, pepper, beans and hemp. It is transmitted almost entirely by the beet leafhopper (Circulifer tenellus). It is one of the most damaging viral diseases of outdoor hemp in the arid western United States.
In practice
Infected plants show cupped, curled and mottled new leaves, yellowing that starts at the tips, stunting and a general "witches' broom" look, sometimes with twisted stems. Early infection can stop a plant flowering properly; late infection does less harm. Indoor grows rarely see it because the vector is an outdoor insect. Management is avoiding hot spots near weedy rangeland, using row covers on young plants, controlling host weeds and pulling infected plants. Testing by PCR confirms it, since symptoms mimic herbicide drift and nutrient problems.
Don't confuse with
- Hop latent viroid: an RNA viroid spread by tools and clones, not insects.
- Herbicide drift: distorted growth on many species at once along a field edge.
- Broad mite damage: twisted tips, but mites are visible under 40x.
An infectious particle of nucleic acid in a protein coat that replicates inside plant cells; on cannabis, often insect-spread and incurable once infected.Hemp is cannabis grown for fibre, seed or other uses and, in many laws, defined as Cannabis sativa with no more than 0.3% THC by dry weight.Small wedge-shaped jumping insects of the family Cicadellidae that suck plant sap; the beet leafhopper (Circulifer tenellus) spreads beet curly top virus to hemp.HLVd, a small infectious RNA that spreads through sap and tools, causing stunting, brittle stems, small loose buds and reduced resin in cannabis; called dudding.The smallest known plant pathogen: a short circular RNA, usually 246-401 nucleotides, with no protein coat and no protein-coding genes, copied by the host's own enzymes.Polyphagotarsonemus latus, a microscopic tarsonemid mite whose toxic feeding twists, glazes and stunts new growth; often mistaken for calcium deficiency or heat stress.Tetranychus urticae, the commonest cannabis mite indoors: a 0.5 mm sap-feeder that stipples leaves pale and spins webbing, breeding fastest in hot, dry rooms.Systematic, regular inspection of plants, traps and roots to detect pests and disease early, identify them correctly and record numbers for decisions.
