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HUM LBR CITRUS EXPERIMENT STATION
LAKE ALFRED, FLORIDA

MAY 12 19'7TITRUS INSECT AND DISEASE SUMMARY
MID-APRIL 1970


F A.S. Uiiv. of FlsOiktewide Index of Abundance


End Mid
-2.0 Mar. Apr.


-1.5


Trend


Rust mite leaves

-----------------_ -7


-1.0


C. red mite
0-_




Texas C. mite


Hi2h for


nites


High for
scales;
whitefly


End
Mar.


I
Mid
Apr.


Trend


^ '7s


N


Vi
A


Whitefly

-/ /


7 /*------>Glover s,
V L s,

S---- Yellow s.


Aphids
Aphids


NOTE: Only pests or conditions of general or current interest are reported.
Forecasts are for 1 month in advance unless otherwise indicated.
Citrus Rust Mite: 71% of groves infested (Norm 61%); 53% economic (Norm 41%).
Population increased slightly and continued above normal and in the high range.
Further increase is expected in May. Highest districts are West (2.00) East (1.45)
and South (1.39).


Citrus Red Mite: 41% of groves infested (Norm 48%);
Population decreased slightly and will be below
Further decrease is expected in April followed by an
is North (.69).


15% economic (Norm 17%).
normal and in the low range.
increase in May. Highest district


Texas Citrus Mite: 25% of groves infested (Norm 41%); 8% economic (Norm 19%).
Population is the lowest for April in 11 years. It will remain below normal and in
the low range. Increase is expected in May. Highest district is South (.50).
Six-spotted Mite: 11% of groves infested (Norm 9%); 3% economic. Population is near
normal. Increase is expected and a few groves will develop important infestations.
Glover Scale: 81% of groves infested (Norm 80%); 9% economic (Norm 22%).
Population is slightly subnormal and at moderate level. Little change is expected.
Highest districts are West (1.00) North (.97) and East (.95).
Purple Scale: 68% of groves infested (Norm 81%); 6% economic (Norm 12%).
This scale is also below normal abundance and will continue near the present low
level. Highest district is West (.93).
Chaff Scale: 49% of groves infested (Norm 63%); 1% economic (Norm 12%).
Population will continue to be low and much below normal in all districts.
Black Scale: 5% of groves infested (Norm 26%); none economic (Norm 10%).
Population is the lowest since 1963 and will remain very low.
Yellow Scale: 59% of groves infested (Norm 66%); 5% economic (Norm 11%).
Population decreased and will remain below normal and low on a statewide basis.
Highest districts are North (.90) and South (.80).
Citrus Snow Scale: 25% of groves infested; 8% with moderate or heavy infestations.
Population is higher than in prior Aprils; however, activity of this scale de-
creased early in April and is not expected to increase until May.
Whitefly: 62% of groves are infested with the larval stage which we regularly report
since it is the most damaging form. (Norm is (63%). However, 91% of groves are infested
with the adult stage and 44% of groves have moderate or heavy adult infestations. This
is the highest adult population since August of 1958 and portends above normal larval
populations in May.
Mealybug population will remain very low until mid-May, then increase rapidly.
Aphids: Population peaked early in April below normal level and quickly decreased.


600 April 17, 1970 WAS


CES Mimeo Series 70-28


W. A. Simanton