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STANDARD VIEW MARC VIEW
CITRUS EXPERIMENT STATION CES Mimeo Series 68-19
LAKE ALFRED, FLORIDA
QUARTERLY CITRUS INSECT AND MITE OUTLOOK
CAUTIONARY NOTE: This Outlook is based on the assumption that weather beyond the
period of the current U.S. Weather Bureau 30-day Outlook will be normal. Therefore,
the forecasts given below cannot be viewed with the same degree of confidence as those
in the "Insect and Disease Summary" usually released twice each month by this Station.
Each pest has more or less regular periods of increase and decrease throughout the
year. Weather conditions (temperature, rain, humidity) may affect populations directly,
or indirectly through effects on predators, parasites and tree growth. Departures from
the average population level may be caused by conditions that occurred months before.
Other fluctuations may reflect recent weather changes. The latter influences can be
forecast only to the extent that weather forecasts are available.
REVIEW OCTOBER THROUGH DECEMBER 1967
The period produced the highest fall rust mite populations in 16 years of record.
Other pests were generally below normal abundance and of little importance.
Rust mite continued to be above normal and at high level throughout the period.
An unexpected increase in late December resulted in moderate or heavy infestations in
68% of groves. Texas citrus mite was below normal and at low level in October and
November. Steady increase resulted in a higher than normal population by mid-December,
with 17% of groves having moderate or heavy infestations. Citrus red mite remained
in the low range and below average until a slight increase in December brought popula-
tion to normal.
Glover scale was the most abundant scale but was in the moderate range and below
the normal of recent years. Only 5 to 9% of groves had important infestations. Purple
scale,chaff scale and yellow scale were all at or near record low levels during the
period. Black scale reached a record low level in October, then increased steadily to.
above normal but moderate level. Snow scale population was the highest on record for
the period, reflecting the general spread of this pest. Fourteen percent of survey
groves are now infested.
Weather in the citrus belt during the period was characterized by abnormally low
rainfall and the absence of temperatures below 320 F except in limited areas. The
generally mild temperature favored December increase of scale insects.
GENERAL FORECAST JANUARY THROUGH MARCH 1968
Rust mite: Population will decrease from the high January level until mid-March.
It will be above normal throughout the period and about 25 percent of groves will have
Texas citrus mite: Population will decrease in February then gradually increase
at mid-March. It will be above normal but at moderate level. About 10 percent of
groves will have heavy infestations.
Citrus red mite: Little change will occur from the low population normal for the
period. Slight increase is expected at mid-March. About 5 percent of groves will have
Six-spotted mite: This mite will increase in a few groves but is not expected to
be destructive through March.
Glover scale will increase gradually and is expected to approach the high range
Purple scale will remain at moderate level.
Yellow scale will increase slightly and will be in moderate abundance.
Black scale is expected to increase in February and subside in March. It will be
above normal abundance but will not become destructive through March.
Snow scale infestations will continue to spread and intensify.
Aphids will start to appear in late February and increase rapidly in March.
Whitefly population will be below normal and low with slight increase in March.
650 -' January 23, 1968 WAS
W. A. Simanton