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Figs
in Texas are affected by three major disease problems. The most important is the
root knot nematode, which is not readily noticed by the average person.
Root-knot
nematodes, Meloidogyne sp., are microscopic, soil inhabiting worms which attack
the plant's root system. They attack and feed on roots, causing them to swell
or gall; thus, interfering with normal uptake of water and nutrients. These galls
are easily seen if root samples are observed.
Nematode problems may go unnoticed
for several years. As a heavy population builds up, the tree loses vigor and declines
gradually. Nematodes contribute to premature fruit drop. To prevent rootknot nematodes
in figs, obtain nematode-free plants and plant in nematode-free soil.
Fig
rust is an important fungus disease that attacks the leaves of figs. It is caused
by Physopella foci. Fig rust first appears as small, yellowish-orange spots on
the leaves. These enlarge slightly and may become very numerous as the season
progresses.
Rust causes complete defoliation of many trees in the state each
year, resulting in ragged-looking trees. In addition, trees defoliated early in
the season may initiate new growth which is often susceptible to cold injury.
Defoliation usually does not occur early enough to cause fruit loss except
in late ripening varieties.
Rust is controlled with neutral copper sprays.
One or two applications made in May or early June usually keep trees in fairly
good condition until after fruit ripens. In very wet seasons one or two additional
applications may be necessary. A good index for spraying is when the first leaves
on the tree have reached full size. The second spray should follow in 3 to 4 weeks.
It is extremely important to get good leaf coverage with the spray material.
Fig souring is a constant problem in Texas. The first step in preventing losses
attributed to souring is to grow recommended varieties, which have a closed eye,
a drooping fruit characteristic and fruit-splitting resistance.
Controlling
insects and using resistant varieties restrain most fruit souring problems most
of the season. Late season infestations may be impracticable to control.
Phymatotricham
omnivore is the number one killer of figs in Texas. This organism is a fungus
primarily associated with alkaline soils. This organism kills the roots, causing
the plant to wither and die in a short time.
There is no resistant variety
or rootstock. The only control, which is impracticable at best, is to completely
recondition the soil before planting. This means completely altering the soil
pH in the area with a soil acidifier. This type of control is not permanent, however.
Several other minor diseases associated with figs can be found but are a
problem only in more humid areas.
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