Biology Reference
In-Depth Information
Fig. 2
Leaf Nematode of
Chrysanthemum.
Wormlike male and female
nematodes cause wedge-
shaped browning between
veins, followed by general
blighting of leaf
a film of water, the disease going from lowest
leaves progressively upward. Almost any variety
may be attacked, but Koreans are particularly
susceptible. The nematodes may not survive the
winter in old dead leaves but they do survive in
living leaves in old crowns.
Control
Keep foliage dry; avoid overhead
watering. Use a mulch to avoid splashing.
Avoid crown divisions; make tip cuttings which
are usually free from nematodes. Dormant plants
can be treated with hot water, 5 min at 122
For
30 min at 112
F.
Aphelenchoides ritzemabosi
Current Nema-
tode
, a bud parasite on black currants and goose-
berries in England; reported from California on
gooseberries. Treat cuttings for 30 min in hot
water, 110
F.
Aphelenchoides subtenuis
Bud and Leaf Nem-
atode
on narcissus, causing scale necrosis.
Reported from the Southeast and Pacific Coast
states.
greenhouse in Connecticut. This is a major pest of
strawberries, celery, and sweet corn in Florida. It
injures Bermuda, centipede, and St. Augustine
grasses and seedlings of slash and long-leaf
pines, being first recorded from pine. Other plants
damaged by
Belonolaimus
species include pea-
nut, pea, lupine, Austrian winter pea, cowpea,
bean, lima bean, soybean, beets, cabbage, cauli-
flower, lettuce, endive, onion, potato, and sweet
potato. The slender worms feed at root tips and
along the sides. Soil fungi enter roots through
feeding punctures. Roots develop short stubby
branches with necrotic lesions; plants are stunted.
On woody plants decline symptoms include chlo-
rosis, twig dieback, premature dropping of fruit
(such as grapefruit), and rapid wilting under
moisture stress. The nematodes seem to be lim-
ited to light, sandy soils.
Control
Rotate crops; cultivate to remove weed
hosts.
Belonolaimus longicaudatus This species may
be responsible for some of the injury ascribed to
B. gracilis
. It occurs in the same southeastern
states and may injure roots of celery, peanut,
grasses, cabbage, bean, and other vegetables.
Potato and soybean are considered especially sus-
ceptible. It has also been reported on magnolia.
Belonolaimus
Belonolaimidae. Sting nematodes, migratory
obligate ectoparasites, usually found free in soil
near growing tips; both sexes long, slender, with
blunt ends; body strongly annulate; about 2 mm
long, stylet long, with well-developed knobs; two
ovaries.
Belonolaimus gracilis
Sting Nematode
on
a wide variety of hosts from Virginia southward,
also reported from New Jersey and from a rose
Bursaphelenchus
Aphelenchoididae. Ecto- and endoparasites;
females (adult) have a vulval flap.