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STANDARD VIEW MARC VIEW
I ES Mimeo Series 69-20
2 Uq Po 'CITRUS EXPERIMENT STATION
C 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 OCTOBER THROUGH DECEMBER 1968
Although one pest species, citrus rust mite, was of wide concern during the period,
many other species were at notably low levels.
Rust mite population moved up to the high range in October, peaked the latter part
of the month and gradually dropped to the normal moderate range by year-end. Infesta-
tion on leaves was slightly below average throughout the period whereas the fruit in-
festation was above normal. Heavy fruit infestations were present in 25 to 36 percent
of groves each month.
Texas citrus mite population remained below normal and very low despite a slight
increase. Only 3 to 8% of groves harbored moderate or heavy infestations, which is
about half the usual number.
Citrus red mite continued below normal abundance and in the low range throughout
the period. Only 2 to 6% of groves had moderate or heavy infestations compared to a
range of 5 to 14%, which is normal for the period.
All scale insect pests except snow scale and green scale were near or below their
normal levels of recent years for October, November and December. Purple scale held
near the 18 year record low levels reported for the end of September 1968. Florida
red scale remained near the 18 year record low that occurred in August and September 1968.
Chaff scale remained through November near its 18 year record low level of September 1968,
then increased slightly. Glover scale and yellow scale were generally the most numerous
scales in groves but these also were below normal abundance. Black scale was at its
normal low level with about 10% of groves harboring moderate or heavy infestations.
Brown soft scale was much below normal abundance whereas green scale was much above.
Citrus snow scale, although of limited distribution, was the only scale of much concern
to growers. It was above average level and continued to increase.
Whiteflies were less numerous than normal.
The period was characterized by below normal temperatures starting in late October.
An early cold spell November 13 and 14 brought freezing temperatures to a few localities.
Fruit maturity occurred 2 to 3 weeks later than average.
GENERAL FORECAST JANUARY THROUGH MARCH 1969
Rust Mite: Population is expected to remain at moderate level with slight decrease
through February and increase in March. About 20% of groves will have heavy infestations.
Texas Citrus Mite: Gradual increase will occur but population is expected to be
moderate. About 8% of groves in scattered locations will develop heavy infestations.
Citrus Red Mite: Population will gradually increase but is expected to remain in the
low range. Heavy infestations are predicted for about 5% of groves in scattered locations.
Six-spotted Mite: Infestations will appear on inside leaves in a few groves. Less
than 2% of groves are expected to develop important infestations.
Glover Scale: Population will change very little. It is expected to be lower than
in recent years and remain at low to moderate level.
Purple scale and chaff scale will remain very low.
Yellow scale is expected to increase slightly but remain in the low range.
Black scale population will remain low and unimportant through March.
Snow scale will occur in some previously uninfested groves and will spread in those
now infested. DV
Aphids will start to appear late in Fbruary a rnpi y in March with a
peak expected early in April.
625 January 16, 1969 WAS JAN 17 1969 W. A. Simanton
I.F.A.S. Univ. of Florida