Agriculture Reference
In-Depth Information
Leafhoppers
All leafhoppers are shaped like elongated triangles, with large heads. Several species
feed on grapes: the grape leafhopper, the three-banded leafhopper, the potato leafhopper,
the variegated leafhopper, and sharpshooters.
CONTROL
Parasitic wasps from the genus
Anagrus
prey on some leafhoppers, as do lacewings, minute
pirate bugs, lady beetles, spiders, and mites. Encourage these beneficials. Control weeds to
reduce the numbers of leafhoppers. Check your vineyard for leafhoppers and if their num-
bers become very high, treat with pyrethrins.
Nematodes
Although there are beneficial nematodes that are used to treat some soil-dwelling grubs,
there are also harmful nematodes that can affect the vineyard. These microscopic round-
worms can feed on plant roots, puncturing and sucking out the inside of individual cells.
Several different kinds affect vineyards, including root knot, dagger, citrus, lesion, and ring
nematodes. Some types are more prevalent in certain soils.
Nematode damage can resemble that caused by other conditions. Vines may lack vigor
and have restricted growth or poor yields. There may be galls or swellings on the roots.
To determine whether you are dealing with harmful nematodes, you will need to take soil
samples and send them to a commercial laboratory for identification.
