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STANDARD VIEW MARC VIEW
CES Mimeo Series 68-10
CITRUS EXPERIMENT STATION
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.
RECENT SITUATION JULY THROUGH SEPTEMBER 1967
Citrus rust mite and black scale attained abnormally high population levels and
were the citrus pests of greatest concern during the period.
Black scale continued to increase through July at which time 73% of groves harbored
moderate or heavy infestations. Decrease began in August but population did not subside
to normal until October. Glover scale was at the normal highlevel in July with 34% of
groves having economic infestations. This level persisted until mid-August which was.
two weeks later than normal, then dropped to the normal low by mid-September. Snow
scale subsided from the population peak attained in June but continued to be much above
normal levels for July through September. Except for lesser snow scale, all other scale
species were near or below normal levels during the period. None were of much im-
portance, including lesser snow scale.
Citrus rust mite populations on both leaves and fruit were above normal level and
in the high range throughout the period. At the peak, which extended from mid-July to
mid-August, 57% of groves harbored moderate or heavy infestations despite wide use of
control measures. Rust mite was still at high level and again increasing at the end of '
September. Texas citrus mite decreased rapidly from the abnormally high June level.
It was still.in the high range at the end of July but had dropped to the normal low
level by September. Citrus red mite dropped out of the high range by mid-July and
continued to be below normal and very low. .A flat mite (Brevipalpus phoenicis) was
more abundant than normal in September, but was of little economic importance.
Whiteflies and mealybug were moderately abundant in July, then subsided to normal
low levels by October. Aphids remained below normal and at low level.
GENERAL FORECAST OCTOBER THROUGH DECEMBER 1967
Rust mite: Population will continue to increase in October; hold at high level
through November then gradually diminish in December. It will be above normal. Between
50 and 60% of groves will develop important infestations in the period.
Texas citrus mite will increase in November but is expected to be below normal
abundance and at moderate level. About 10% of groves will develop important infestations.
Citrus red mite will gradually increase mid-October through December. Infestations
are expected to be fewer and lighter than average for the period. Moderate to heavy
infestations will occur in about 15% of groves. These will be most destructive to
young trees in dry locations.
Glover scale: These scales will gradually
Purple scale: increase but none are expected
Chaff scale: to exceed normal levels or
Yellow scale: enter the high range.
Snow scale will continue to increase and produce a fall brood of crawlers. Crawlers
carried by picking crews on clothing and equipment are likely to start new infestations.
650 October 17, 1967 WAS W. A. Simanton