University of Florida IFAS
Ft. Lauderdale ARC Research Report FL-77-1
Second Research Program Report on Chemical Control
of the Citrus Blackfly, Aleurocanthus woglumi Ashby
James A. Reinert HUIME L BRARY
University of Florida, ARC, IFAS
Ft. Lauderdale, Florida AUC 14 198
January 17, 1977
I.F.A.S. Univ. of Florida
This report is an update of research completed or-plianne '-sice-the--~
last report Mimeo Report ARC-FL-76-2, September 10, 1976 was completed.
The following summarizes the experiments completed or in progress for
control of the citrus blackfly, Aleurocanthus woglumi Ashby, by chemical
1. An experiment was conducted to evaluate systemic activity of
several insecticides when applied only to the upper surface of the infested
leaves. Spray tank solutions of the insecticides listed in Table 1 were
painted on 50 leaves per tree in this study.
This experiment was considered unsuccessful since very poor control
was obtained at 2 weeks post-treatment. Solutions were mixed one day, and
due to inclement weather, were not applied until the following day. Apparently
this delay in application resulted in almost complete loss of insecticidal
activity by all the chemicals tested. This experiment has been re-established.
Table 1. Insecticides used in upper-surface leaf treatment test.
Insecticide Ib AI/100 gal Insecticide Ib AI/100 gal
Acephate 1 Oxydemetonmethyl 0.5
Acephate 0.5 Oxydemetonmethyl 0.25
Acephate 0.25 Azinphos-methyl 0.5
Dimethoate 0.5 Azinphos-methyl 0.25
Dimethoate 0.25 Untreated Check 0
2. An experiment was conducted to compare foliar spray application
with mist blower treatments of acephate and to determine the lowest treat-
ment'rate which would give acceptable control. Rates of application for
both treatment methods are given in Table 2. Each treatment was applied
3 times at 1 week intervals. From Table 2, it is apparent that all treat-
ment levels of acephate by both treatment methods gave excellent control
of the citrus blackfly.
,le 2. Percentage control of citrus blackfly1 on dooryard citrus treated with
acephate on September 28, and October 5 and 12, 1976 (6 reps.).
Type of Rate 2
Treatment l b AI/100 % control
gal following initial treatment
1 wk 2 wk 3 wk
L P L P L P
iar spray 0.5 94.0a 95.6a 99.3a 97.5a 99.4a 99.8a
iar spray 1.0 96.5a 89.9a 99.5a 99.6a 99.9a 99.6a
t blower 2.5 85.6a 79.2a 100a 97.7a 100a 99.la
t blower 2.0 92.3a 86.6a 98.7a 98.0a 99.0a 99.3a
t blower 1.5 88.3a 89.0a 98.7a 97.8a 95.3a 96.8a
t blower 1.0 68.8b 69.3b 82.6b 82.2b 96.1a 95.4a
created 0 Oc Oc Oc Oc Ob Ob
= 2nd and 3rd instars; P = pupa
justed by Abbotts' Formula. Means in
tter are significantly different (P =
a column not followed by the same
0.01) (Duncan's multiple range test).
3. A third experiment.was conducted to evaluate additional insecticides
by foliar treatment to control citrus blackfly. Four orange trees in containers
infested with citrus blackfly larvae were treated with each insecticide or in-
secticide combination as listed in Table 3.
Table 3 shows that azinphos-methyl, dimethoate and oxydemetonmethyl
provided better control than the ethion and ethion + oil combinations.
Best control was provided when the trees were treated with dimethoate.
Table 3. Comparative control of citrus blackfly by different insecticides
applied by foliar spray (4 reps.).
Chemical AI/100 Gal % Control
(LB) 2 Wk. 4 Wk.
L P L P
Dimethoate 4EC '
Azinphos-methyl 2 EC
Oxydemetonmethyl 2 EC
Ethion 4 EC
Ethion + Oil 0.625 EC
Ethion + Oil 0.47 EC
0.37 + 0.7
0.37 + 0.5
IAdjusted to Untreated Check by Abbotts' Formula
L = 2nd and 3rd instar larvae
P = Pupae
4. Aldicarb is being re-evaluated for control of citrus blackfly on
citrus nursery stock in containers. -Plants are being reinfested throughout
the test to insure a continual pressure of viable insects on each plant in
the test. Table 4 gives the percentage of live citrus blackfly on aldicarb
treated vs. untreated check trees up to 7 weeks post-application. This test
will continue until no control is provided by the aldicarb treatments.
Table 4. A comparison of live citrus blackfly on citrus .trees in containers
either treated or not treated with aldicarb at 10 Ib AI/Acre (4 reps.).
% alive at weeks post-treatment
Insecticide 2 4 5 6 7
L P L P L P L P L P
Aldicarb 10 G 12.4 7.0 3.2 0 4.7 1.6 12.9 0 8.6 0
Untreated Check 74.5 88.6 85.0 97.3 85.7 98.8 54.6 95.2 62.0 93.4
L = 1st, 2nd and 3rd instar larvae
P = Pupae
5. A field study has been established jointly between IFAS and
DPI to determine the feasibility of an eradication program for the citrus
blackfly. In this test acephate is being evaluated at 0.5 Ib AI/100 gal
by foliar spray and 2.0 Ib AI/100 gal by mist blower. Acephate treatments
are being compared with malathion at 1.25 Ib AI/100 gal by foliar spray and
untreated checks. Each of the 4 treatments are being applied to 4 city
blocks. Within each city block all citrus, mangos, Surinam cherries, and
any other plants which act as hosts for the citrus blackfly are being treated.
These treatments will be applied 3 times at- 21 day intervals, and the degree
of control will be evaluated throughout the test.
6.. Residue samples of fruit and leaves have been and are being taken
from each of the above tests to determine the safety of each pesticide to
man and the environment. Residues will also be monitored in soil under
treated trees and adjacent streams from test 5 above. The residue deter-
minations are being made at the AREC, Lake Alfred.
1. Determine residues of acephate on foliage and fruit to aid in
establishing safe re-entry dates and waiting periods before harvesting
fruit from acephate treated citrus and other tropical fruit crops.
2. Determine environmental impact of an eradication program for
citrus blackfly including pesticide effect on non-target organisms such
as predators, parasites, and other citrus pests already established in the
system. Determine residues of pesticides on citrus as well as non citrus
plants. Determine residues of pesticides in soil, surface and ground water.
3. Evaluate effect of acephate and/or other insecticides on non-target
insects including the parasites of the citrus blackfly.
4. Determine best method of application for eradication or manage-
ment of the citrus blackfly.
5. Evaluate additional insecticides and formulations for control of