(excerpt)
The Colorado potato beetle, Leptinotarsa decemlineata (Say), is a serious pest of  tomatoes grown in this country. This beetle is also developing resistance to several classes of chemical insecticides including most of the carbamates, chlorinated hydrocarbons, and organophosphates (Forgash 1981). and most recently to the pyrethroids. According to figures in a report released by Schwartz and Klassen (1981). the value of the tomato crop in the CSA in 1978 was placed at $914,121,000 and crop loss due to Colorado potato beetle (CPB) damage alone would be 93% of its value if no control were undertaken. These figures along with the fact that the CPB is developing resistance dictate the need for. and development of, alternative control measures

Cantelo, W. W

Cantwell, G. E

English

ValpoScholar

The Great Lakes Entomologist 
Volume 17 
Number 3 - Fall 1984 Number 3 - Fall 1984 Article 6 
October 1984 
Control of the Colorado Potato Beetle (Coleoptera: 
Chrysomelidae) on Tomatoes with Bacillus Thuringiensis Var. 
Thuringiensis 
G. E. Cantwell 
USDA Research Center 
W. W. Cantelo 
USDA Research Center 
Follow this and additional works at: https://scholar.valpo.edu/tgle 
 Part of the Entomology Commons 
Recommended Citation 
Cantwell, G. E. and Cantelo, W. W. 1984. "Control of the Colorado Potato Beetle (Coleoptera: 
Chrysomelidae) on Tomatoes with Bacillus Thuringiensis Var. Thuringiensis," The Great Lakes 
Entomologist, vol 17 (3) 
Available at: https://scholar.valpo.edu/tgle/vol17/iss3/6 
This Peer-Review Article is brought to you for free and open access by the Department of Biology at ValpoScholar. 
It has been accepted for inclusion in The Great Lakes Entomologist by an authorized administrator of ValpoScholar. 
For more information, please contact a ValpoScholar staff member at scholar@valpo.edu. 
1984 THE GREAT LAKES ENTOMOLOGIST 145 
CONTROL OF THE COLORADO POTATO BEETLE 
(COLEOPTERA: CHRYSOMELIDAE) ON TOMATOES WITH 
BACILLUS THURINGIENSIS VAR. THURINGIENSIS 
G. E. Cantwell and W. W. Cantelo l 
The Colorado potato beetle, Leptinotarsa decemlineata (Say), is a serious 
tomatoes grown in this country. This beetle is also developing resistance to 
of 
chemical insecticides including most 
of the carbamates, chlorinated hydrocarbons, and 
organophosphates tForgash 1981). and most recently to the pyrethroids. According to 
figures in a reiX)f( released by Schwartz and Klassen (1981). the value of the tomato crop 
in the CSA in 1978 was placed at 5914,121,000 and crop loss due to Colorado potato 
beetle (CPB) damage alone would be 93% of its value if no control were undertaken. 
These tlgures along with the fact that the CPB is developing resistance dictate the need 
for. and de\'e!opment of, alternative control measures. 
For over 15 years it has been known that the bacterium, Bacillus thuringiensis (B.t.) 
produces an exotoxin that will kill larvae of the CPB (Burgerjon, et. al. 1969). This 
exotoxin. the so-called beta-exotoxin r thuringiensin is produced by several varieties of 
B.t. including the \ar1ety thuringiensis (B.u.). Earlier laboratory work (Cantwell and 
Cantelo 1981 , indicated that this exotoxin from several sources has, against neonate CPB 
larvae. a measurable LDso and that its quantity and quality can be determined by bioassay 
and high pressure liquid chromotography tcchniques. 
The pUf]X)se of the work reported here was to test the efficacy of two experimental 
preparations of B.u. in field trials against the CPB n bo h experimental plots and under 
commercial growing conditions. The experimental material used in these tests has not as 
yet been cleared for use by the E.P.A. 
MATERIALS AND METHODS 
Two experimental preparations f Bacillus thuringiellsis vaL thuringiensis were 
sprayed on tomato plants for beetle control. One, preparation produced by Sandoz, Inc. of 
Wasco. CA. labeled SAN 41OSCn, contained 2.0 gil of the beta-exotoxin. The other 
product wa, furnished by Biochem Products of Montchanin, DE, labeled strain # 19, and
contained 0.5 Q; 1 acth'e ingredient. 
The test in which the Sandoz product was used consisted of 18 plots ca. 250 m2 in size 
and located at the CSDA Beltsville, MD, Agricultural Research Center. Nine of these 
plots were used as untreated controls and the remaining nine were sprayed with three 
levels of the B.u.. each replicated three times. B.Ll. applications were made at 450 psi 
with a tractor towed Agrotec sprayer equipped with drop nozzles at rates of either 1.17, 
2.34. or 7.0 I in 935 I of water per hectare at about weekly intervals beginning 3 June 
1983. Tomatoes were of the Supersonic cultivar. 
Tests with the Biochem preparation were conducted on two commercial grower's farms 
near Cambridge. ~ID. On each farm three 0.3-ha plots were established (an untreated 
plot. a B.r.t. treated plot. and a plot using conventional pest controls). On one farm the 
B.u. 
was applied at 1 part:500 parts water (v/v) and the other at 1:1000. Sprays were 
applied to the run-off-point with a back-pack sprayer at approximately weekly intervals. 
Plots were planted with processing tomatoes 
of either the Campbell-28 or YF-134 
cultivars. Transplants were set out in rows 1.2 m apart with 30 cm between plants within 
the row. Pre-emergem herbicides were applied and the plots were cultivated with a 
\'A,'A'O,h'A Laboratory. CSDA-. Agricultural Research Center, Beltsville, MD 20705. 
1
Cantwell and Cantelo: Control of the Colorado Potato Beetle (Coleoptera: Chrysomelidae)
Published by ValpoScholar, 1984
146 THE GREAT LAKES ENTOMOLOGIST Vol. 17, No.3 
follow-up weed control of either Eptam or Tillam. The transplants received a side dressing 
of 
10-10-10 fertilizer. All plots received 
fungicide applications (i.e., Dithane or Bravo) at 
time of crown fruit appearance. In those plots receiving conventional pest controls, 
Vydate was applied twice during the season. Yield data were taken at harvest. 
To determine efficacy of the B.t.t. preparations and conventional treatment, counts 
were made prior to spray applications of numbers in four life stages of th  beetle: adults, 
egg masses, 1st & 2nd instar larvae, and 3rd & 4th instar larvae. Statistical analyses were 
used to compare means. 
RESULTS AND DISCUSSION 
Beltsville tests. Surveys taken at nearly 7 -day intervals throughout the test indicated no 
consistent significant differences among or between treated and untreated plots in 
numbers of egg masses or I st or 2nd instar larvae. Two weeks after egg masses were first 
discovered, no significant differences were observed among numbers of 3rd and 4th instar 
larvae or adults, however, by the 15th of June, large numbers of older larvae were counted 
in the untreated plots. These numerous 3rd and 4th ins tar larvae and the resulting adults 
completely defoliated three of the untreated plots as indicated in Figure I, and produced 
significant differences between numbers in these life stages in the remaining untreated and 
treated plots. A measure of the effectiveness of the combined B.t.t. treatments when 
compared to the combined untreated plots is evident in the tremendous reductions in the 
treated plots in populations of older larvae and adults which were 99.9% and 98.6% 
respectively (Table I). 
In most of the treated plots very few 3rd or 4th ins tars or adults were present and 
because of this there were no significant differences among the three treatment levels. 
From these data, we are unable to determine or predict the lowest level that would afford 
economic protection to different levels of beetle infestation. 
Cambridge 
tests. In the test plot treated with 
B.t.t. at the 1:500 rate, significant 
differences from the untreated plots were noted as early as the 1st of June in both numbers 
of 
egg masses and young larvae. At this time the number 
of egg masses per plant in the 
untreated plot was nearly 1.25 which, a week later, resulted in nearly 10 I st and 2nd ins tar 
larvae per plant. By 23 July, the number of 3rd and 4th instar larvae per plant averaged 
5.14. A week later there were I1.5 adults per plant which were sufficient in number to 
completely defoliate these immature plants in this untreated plot, resulting in no yield. At 
no 
time during the test did the average numbers 
of 3rd or 4th instar larvae or adults in the 
B.t.t. treated plot reach 0.1 per plant. 
The effect of the B.t.t. on the Colorado potato beetle is in preventing 1st and 2nd instar 
larvae from becoming 3rd instars and hence 4th instars and adults. At a dilution of 1:500 
the percent reduction of 3rd instar larvae and adults due to B .t.t. tr atment exceeded 99% 
and nearly 95% respectively. The I: 1000 dilution produced similar results. These results 
were almost identical to those f the Vydate treatment, however, (see Table 2) the 
Table I. Percent reduction of the Colorado potato beetle by life stage on tomato plants 
either untreated or treated with Bacillus thuringiensis var. thuringiensisa at Beltsville, 
MD. 
Stage Untreatedb Treatedb Reduction (%) 
egg mass 371 41 88.9 
1st & 2nd instar 1814 992 45.3 
3rd & 4th instar 1345 I 99.9 
adult 1221 17 98.6 
aB.t.t. Experimental preparation SAN 410SCn supplied by Sandoz, Inc. 
bTotal numbers in each life stage on plants sampled. 
2
The Great Lakes Entomologist, Vol. 17, No. 3 [1984], Art. 6
https://scholar.valpo.edu/tgle/vol17/iss3/6
1984 THE GREAT LAKES ENTOMOLOGIST 147 
3RD & 4TH INSTAR/PLANT 
5.0n·--------------------, 
5.5 1\ location 
. I \ •._._ .• ~ UNTREATED 
5.0 r- / \ A---- ..... #2 UNTREATED 
, I \ 
• ...........• #3 UNTREATED 
] I \ I ' 
_ #4.5.6. - TREATED 
4.5 r I \ .• 
40:- f \./ '. 

3.5f.. / ~I \ 

I ;' \ \ 

f / \ .. 
2.5 I .. \ \ 
:./ \ \ :I 1 \ \ 
I ; \ \1.5 f./ J..... \ ":("" ,/" , 
1,0 l / ....../ .,..... ,....\ ......... '<':':':, ...... ~.,;::_ .... .. 
O.5~·· 1;/ ~ ......... ,,;." -I

o.ol i/. • --r--- ..:'l:-....,::-:._._.,.;.... • 
8 15 23 28 5 11 18 25 1 
JUNE JUl Y AUG 
ADULTS/PLANT 
10.0 16.6, DEFOLIATED 
1.0 location 
•._._.• #1 
- UNTREATED 
...--- .... #2 
- UNTREATED ............. #3-
UNTREATED 
0.9 
0.8 
_______ #4.5.6. TREATED 
0.7 ~. 
0.6 
;.. i \ 
/ \i0.5 \i \ 
", ! \ 
• / ,{ \. i 
0.3 .. 
1\1 /, './ ./ i', \ 1 
0.2 - ,/ /".' "".... \ 
i /1 ",,1. \.! ' .... , __ ~... 
0.0 ~~~ .../. ~ . ==m~' 8 15 23 28 5 11 18 25 1 
JUNE JULY AUG 
Fig. I. Effect on numbers of Colorado potato beetle 3rd and 4th instar larva of adults on tomato plants 
due!O weekly applications of spray containing Bacillus thuringiensis var. thuringiensis. Location 
# I tplots 1. 2. and 3 untreated): location #2 (plots 4, 5, and 6 untreated); location #3 (plots 7, 8, 
and 9 untrearedl: locations #4, 5, and 6 (plots 10-18 treated) at Beltsville, MD. 
chemical was much more effective in reducing the number of egg masses and 1st and 2nd 
instar larvae. 
No si!!nificant differences were noted i  number of beetles between B. .t. and 
conventional treatments. nor was there a difference in tomato yield. The conventional and 
B .t.t. treared plants yielded 28.5 and 30.5 lbs. of ripe tomatoes per 150 row ft. This low 
tomaro production was partly due to severe drought which also deactivated herbicides and 
allowed annual weeds to effectively compere with the crop. 
3
Cantwell and Cantelo: Control of the Colorado Potato Beetle (Coleoptera: Chrysomelidae)
Published by ValpoScholar, 1984
148 THE GREAT LAKES EKTOMOLOGIST Vol. 17, NO.3 
NO.lPLANT3rd&4th INSTAR 
6.0,------------------------, 
5.0 ;\ 
I \ 

I \ 

I \ 

4.0 
I \ 
'--' UNTREATED 
I \ 
I \ --BT 
I \ 
I \ 
.• _ •• COMMERCIAL3.0 I \ ,I 
I 
'. DEFOLIATED
I 2.0 
I 
I 
I 
I 1.0 
I I 
0.5 I I 
I I I ...... -j I I 
17 24 9 16 23 30 8 12 20 28 8 22 30 
JUNE JULY AUGUST 
NO.lPLANT ADUL TS 
12 
t,11 
,I , ,
, ,10 
, 
 ' DEFOLIATED 
9 ,I 
8 ,I 
7· 
I ,
I 
•__ . UNTREATED 6 ,

, 

--BT5 , 

I •• - •• COMMERCIAL4 , 

,I3 
,

2 
,I 
I
"""''''- ..... _-- .. -......... 
.. - .. ....,..- .. 

17 24 
9 
16 23 30 8 12 20 28 8 22 30 
JUNE JULY AUGUST 
Fig. 2. Effects on numbers of Colorado potato beetle 3rd and 4th instar larvae or adults on tomato 
plants due o weekly applications f Bacillus thuringiellsis var. fhuringiensis at a dilution of 1:500 
at Cambridge, MD. 
4
The Great Lakes Entomologist, Vol. 17, No. 3 [1984], Art. 6
https://scholar.valpo.edu/tgle/vol17/iss3/6
1984 THE GREAT LAKES ENTOMOLOGIST 149 
NOJPLANT 3rd&4th INSTAR 
2.00 r-----------------------.---, 
[ \ 
1.80 [ \ 
[ \ 
I \ 
I \ 1.60 
._-_. UNTREATED I \ 
1.40 [ \ 
---BT I \ 
[ \1.20 _._.- COMMERCIAL [ \ 
[ \ 
[ \1.00 
I \ 
I \0.80 
/I \ \0.60 ~ 
".. 
/1'.1"'/' ".. ...10.40 
".­
,- /
,-
/ / 
,-
./ 
0.20 
17 23 30 8 12 20 28 8 22 30 
JUNE JULY AUGUST 
NO.lPLANT ADULTS 
2.0 r-------------------------...... 
I 
I 
I 
I 
I 
._-_. UNTREATED1.5 I 
I 
--BT 
I [ 
_._.- COMMERCIAL 
[ 
[ I ~1.0 [ 
I 
I 
0.5 ,.. ............1 /i 

0.4 / I 
0.3 

02 
 ...... ----~-_ // /
- .- '. -.... / - .' 
• 
~ 
0.1 ..... 8'. e''''-''' ,,,XL ::1~~-~1~7~~23~~~30~~~8==~~12~~2~0~~2~8~~~8~~22~~~30· 
JUNE JULY AUGUST 
Fig. 3. Effects on numbers of Colorado pOlato beede 3rd and 4th instar larvae or adults on tomato 
plants due to \\ ekly applications of Bacillus thuringiensis vaL thuringiensis at a dilution of I: 1000 
at Cambridge. 1m. 
5
Cantwell and Cantelo: Control of the Colorado Potato Beetle (Coleoptera: Chrysomelidae)
Published by ValpoScholar, 1984
150 THE GREAT LAKES ENTOMOLOGIST Vol. 17, No, 3 
Table 2. Percent reduction of the Colorado potato beetle on tomato plants treated with 
either Bac llus thurillgiellsis var. lhuringiensis (B.t.t.)" or Vydate compared to untreated 
plants at Cambridge, MD. 
B.t.t. (I :500) B.t.!. (I: 1000) 
egg 57.6 0.0 100.0 
1st & 2nd instar 34.3 0.0 99.2 
3rd & 4th instar 99.1 99.5 98.5 
adult 94.8 88.9 94.2 
"B.t.t. Experimental preparation of crude supernatant, strain #19 supplied by Biochem 
Products. 
LITERATURE CITED 
Burgerjon, A., G. Biache, and P. Cals. 1969. Teratology of the Colorado potato beetle. 
Leptinotarsa decemlineata, as provoked by larval administration of the thermostable 
toxin Bacillus thuringiensis. J. Invertebr. Pathol. 14:274-278. 
Cantwell, G. E. and W. W. Cantelo. 1981. Bacillus thuringiensis, a potential control 
agent for the Colorado potato beetle. Amer. Potato 1. 58:457-468. 
Forgash, A. 1. 1981. Insecticide resistance of the Colorado potato beetle, Leptinotarsa 
decemlineata (Say). p. 34-46 in 1. H. Lashomb and R. C. Casagrande (eds.). 
Advances in potato pest management. Hutchinson Ross Pub. Co., Stroudsburg, PA. 
Schwartz, P. H. and W. Klassen. 1981. Estimate of losses caused by insects and mites to 
agricultural crops. CRC Handbook of Pest Management in Agriculture. I: 15~77. 
6
The Great Lakes Entomologist, Vol. 17, No. 3 [1984], Art. 6
https://scholar.valpo.edu/tgle/vol17/iss3/6


Control of the Colorado Potato Beetle (Coleoptera: Chrysomelidae) on Tomatoes with \u3ci\u3eBacillus Thuringiensis\u3c/i\u3e Var. \u3ci\u3eThuringiensis\u3c/i\u3e

Valparaiso University

The Great Lakes Entomologist Volume 17 Number 3 - Fall 1984 Number 3 - Fall 1984 Article 6 October 1984 Control of the Colorado Potato Beetle (Coleoptera: Chrysomelidae) on Tomatoes with Bacillus Thuringiensis Var. Thuringiensis G. E. Cantwell USDA Research Center W. W. Cantelo USDA Research Center Follow this and additional works at: https://scholar.valpo.edu/tgle  Part of the Entomology Commons Recommended Citation Cantwell, G. E. and Cantelo, W. W. 1984. "Control of the Colorado Potato Beetle (Coleoptera: Chrysomelidae) on Tomatoes with Bacillus Thuringiensis Var. Thuringiensis," The Great Lakes Entomologist, vol 17 (3) Available at: https://scholar.valpo.edu/tgle/vol17/iss3/6 This Peer-Review Article is brought to you for free and open access by the Department of Biology at ValpoScholar. It has been accepted for inclusion in The Great Lakes Entomologist by an authorized administrator of ValpoScholar. For more information, please contact a ValpoScholar staff member at scholar@valpo.edu. 1984 THE GREAT LAKES ENTOMOLOGIST 145 CONTROL OF THE COLORADO POTATO BEETLE (COLEOPTERA: CHRYSOMELIDAE) ON TOMATOES WITH BACILLUS THURINGIENSIS VAR. THURINGIENSIS G. E. Cantwell and W. W. Cantelo l The Colorado potato beetle, Leptinotarsa decemlineata (Say), is a serious tomatoes grown in this country. This beetle is also developing resistance to of chemical insecticides including most of the carbamates, chlorinated hydrocarbons, and organophosphates tForgash 1981). and most recently to the pyrethroids. According to figures in a reiX)f( released by Schwartz and Klassen (1981). the value of the tomato crop in the CSA in 1978 was placed at 5914,121,000 and crop loss due to Colorado potato beetle (CPB) damage alone would be 93% of its value if no control were undertaken. These tlgures along with the fact that the CPB is developing resistance dictate the need for. and de\'e!opment of, alternative control measures. For over 15 years it has been known that the bacterium, Bacillus thuringiensis (B.t.) produces an exotoxin that will kill larvae of the CPB (Burgerjon, et. al. 1969). This exotoxin. the so-called beta-exotoxin r thuringiensin is produced by several varieties of B.t. including the \ar1ety thuringiensis (B.u.). Earlier laboratory work (Cantwell and Cantelo 1981 , indicated that this exotoxin from several sources has, against neonate CPB larvae. a measurable LDso and that its quantity and quality can be determined by bioassay and high pressure liquid chromotography tcchniques. The pUf]X)se of the work reported here was to test the efficacy of two experimental preparations of B.u. in field trials against the CPB n bo h experimental plots and under commercial growing conditions. The experimental material used in these tests has not as yet been cleared for use by the E.P.A. MATERIALS AND METHODS Two experimental preparations f Bacillus thuringiellsis vaL thuringiensis were sprayed on tomato plants for beetle control. One, preparation produced by Sandoz, Inc. of Wasco. CA. labeled SAN 41OSCn, contained 2.0 gil of the beta-exotoxin. The other product wa, furnished by Biochem Products of Montchanin, DE, labeled strain # 19, andcontained 0.5 Q; 1 acth'e ingredient. The test in which the Sandoz product was used consisted of 18 plots ca. 250 m2 in size and located at the CSDA Beltsville, MD, Agricultural Research Center. Nine of these plots were used as untreated controls and the remaining nine were sprayed with three levels of the B.u.. each replicated three times. B.Ll. applications were made at 450 psi with a tractor towed Agrotec sprayer equipped with drop nozzles at rates of either 1.17, 2.34. or 7.0 I in 935 I of water per hectare at about weekly intervals beginning 3 June 1983. Tomatoes were of the Supersonic cultivar. Tests with the Biochem preparation were conducted on two commercial grower's farms near Cambridge. ~ID. On each farm three 0.3-ha plots were established (an untreated plot. a B.r.t. treated plot. and a plot using conventional pest controls). On one farm the B.u. was applied at 1 part:500 parts water (v/v) and the other at 1:1000. Sprays were applied to the run-off-point with a back-pack sprayer at approximately weekly intervals. Plots were planted with processing tomatoes of either the Campbell-28 or YF-134 cultivars. Transplants were set out in rows 1.2 m apart with 30 cm between plants within the row. Pre-emergem herbicides were applied and the plots were cultivated with a \'A,'A'O,h'A Laboratory. CSDA-. Agricultural Research Center, Beltsville, MD 20705. 1Cantwell and Cantelo: Control of the Colorado Potato Beetle (Coleoptera: Chrysomelidae)Published by ValpoScholar, 1984146 THE GREAT LAKES ENTOMOLOGIST Vol. 17, No.3 follow-up weed control of either Eptam or Tillam. The transplants received a side dressing of 10-10-10 fertilizer. All plots received fungicide applications (i.e., Dithane or Bravo) at time of crown fruit appearance. In those plots receiving conventional pest controls, Vydate was applied twice during the season. Yield data were taken at harvest. To determine efficacy of the B.t.t. preparations and conventional treatment, counts were made prior to spray applications of numbers in four life stages of th  beetle: adults, egg masses, 1st & 2nd instar larvae, and 3rd & 4th instar larvae. Statistical analyses were used to compare means. RESULTS AND DISCUSSION Beltsville tests. Surveys taken at nearly 7 -day intervals throughout the test indicated no consistent significant differences among or between treated and untreated plots in numbers of egg masses or I st or 2nd instar larvae. Two weeks after egg masses were first discovered, no significant differences were observed among numbers of 3rd and 4th instar larvae or adults, however, by the 15th of June, large numbers of older larvae were counted in the untreated plots. These numerous 3rd and 4th ins tar larvae and the resulting adults completely defoliated three of the untreated plots as indicated in Figure I, and produced significant differences between numbers in these life stages in the remaining untreated and treated plots. A measure of the effectiveness of the combined B.t.t. treatments when compared to the combined untreated plots is evident in the tremendous reductions in the treated plots in populations of older larvae and adults which were 99.9% and 98.6% respectively (Table I). In most of the treated plots very few 3rd or 4th ins tars or adults were present and because of this there were no significant differences among the three treatment levels. From these data, we are unable to determine or predict the lowest level that would afford economic protection to different levels of beetle infestation. Cambridge tests. In the test plot treated with B.t.t. at the 1:500 rate, significant differences from the untreated plots were noted as early as the 1st of June in both numbers of egg masses and young larvae. At this time the number of egg masses per plant in the untreated plot was nearly 1.25 which, a week later, resulted in nearly 10 I st and 2nd ins tar larvae per plant. By 23 July, the number of 3rd and 4th instar larvae per plant averaged 5.14. A week later there were I1.5 adults per plant which were sufficient in number to completely defoliate these immature plants in this untreated plot, resulting in no yield. At no time during the test did the average numbers of 3rd or 4th instar larvae or adults in the B.t.t. treated plot reach 0.1 per plant. The effect of the B.t.t. on the Colorado potato beetle is in preventing 1st and 2nd instar larvae from becoming 3rd instars and hence 4th instars and adults. At a dilution of 1:500 the percent reduction of 3rd instar larvae and adults due to B .t.t. tr atment exceeded 99% and nearly 95% respectively. The I: 1000 dilution produced similar results. These results were almost identical to those f the Vydate treatment, however, (see Table 2) the Table I. Percent reduction of the Colorado potato beetle by life stage on tomato plants either untreated or treated with Bacillus thuringiensis var. thuringiensisa at Beltsville, MD. Stage Untreatedb Treatedb Reduction (%) egg mass 371 41 88.9 1st & 2nd instar 1814 992 45.3 3rd & 4th instar 1345 I 99.9 adult 1221 17 98.6 aB.t.t. Experimental preparation SAN 410SCn supplied by Sandoz, Inc. bTotal numbers in each life stage on plants sampled. 2The Great Lakes Entomologist, Vol. 17, No. 3 [1984], Art. 6https://scholar.valpo.edu/tgle/vol17/iss3/61984 THE GREAT LAKES ENTOMOLOGIST 147 3RD & 4TH INSTAR/PLANT 5.0n·--------------------, 5.5 1\ location . I \ •._._ .• ~ UNTREATED 5.0 r- / \ A---- ..... #2 UNTREATED , I \ • ...........• #3 UNTREATED ] I \ I ' _ #4.5.6. - TREATED 4.5 r I \ .• 40:- f \./ '. 3.5f.. / ~I \ I ;' \ \ f / \ .. 2.5 I .. \ \ :./ \ \ :I 1 \ \ I ; \ \1.5 f./ J..... \ ":("" ,/" , 1,0 l / ....../ .,..... ,....\ ......... '<':':':, ...... ~.,;::_ .... .. O.5~·· 1;/ ~ ......... ,,;." -Io.ol i/. • --r--- ..:'l:-....,::-:._._.,.;.... • 8 15 23 28 5 11 18 25 1 JUNE JUl Y AUG ADULTS/PLANT 10.0 16.6, DEFOLIATED 1.0 location •._._.• #1 - UNTREATED ...--- .... #2 - UNTREATED ............. #3-UNTREATED 0.9 0.8 _______ #4.5.6. TREATED 0.7 ~. 0.6 ;.. i \ / \i0.5 \i \ ", ! \ • / ,{ \. i 0.3 .. 1\1 /, './ ./ i', \ 1 0.2 - ,/ /".' "".... \ i /1 ",,1. \.! ' .... , __ ~... 0.0 ~~~ .../. ~ . ==m~' 8 15 23 28 5 11 18 25 1 JUNE JULY AUG Fig. I. Effect on numbers of Colorado potato beetle 3rd and 4th instar larva of adults on tomato plants due!O weekly applications of spray containing Bacillus thuringiensis var. thuringiensis. Location # I tplots 1. 2. and 3 untreated): location #2 (plots 4, 5, and 6 untreated); location #3 (plots 7, 8, and 9 untrearedl: locations #4, 5, and 6 (plots 10-18 treated) at Beltsville, MD. chemical was much more effective in reducing the number of egg masses and 1st and 2nd instar larvae. No si!!nificant differences were noted i  number of beetles between B. .t. and conventional treatments. nor was there a difference in tomato yield. The conventional and B .t.t. treared plants yielded 28.5 and 30.5 lbs. of ripe tomatoes per 150 row ft. This low tomaro production was partly due to severe drought which also deactivated herbicides and allowed annual weeds to effectively compere with the crop. 3Cantwell and Cantelo: Control of the Colorado Potato Beetle (Coleoptera: Chrysomelidae)Published by ValpoScholar, 1984148 THE GREAT LAKES EKTOMOLOGIST Vol. 17, NO.3 NO.lPLANT3rd&4th INSTAR 6.0,------------------------, 5.0 ;\ I \ I \ I \ 4.0 I \ '--' UNTREATED I \ I \ --BT I \ I \ .• _ •• COMMERCIAL3.0 I \ ,I I '. DEFOLIATEDI 2.0 I I I I 1.0 I I 0.5 I I I I I ...... -j I I 17 24 9 16 23 30 8 12 20 28 8 22 30 JUNE JULY AUGUST NO.lPLANT ADUL TS 12 t,11 ,I , ,, ,10 ,  ' DEFOLIATED 9 ,I 8 ,I 7· I ,I •__ . UNTREATED 6 ,, --BT5 , I •• - •• COMMERCIAL4 , ,I3 ,2 ,I I"""''''- ..... _-- .. -......... .. - .. ....,..- .. 17 24 9 16 23 30 8 12 20 28 8 22 30 JUNE JULY AUGUST Fig. 2. Effects on numbers of Colorado potato beetle 3rd and 4th instar larvae or adults on tomato plants due o weekly applications f Bacillus thuringiellsis var. fhuringiensis at a dilution of 1:500 at Cambridge, MD. 4The Great Lakes Entomologist, Vol. 17, No. 3 [1984], Art. 6https://scholar.valpo.edu/tgle/vol17/iss3/61984 THE GREAT LAKES ENTOMOLOGIST 149 NOJPLANT 3rd&4th INSTAR 2.00 r-----------------------.---, [ \ 1.80 [ \ [ \ I \ I \ 1.60 ._-_. UNTREATED I \ 1.40 [ \ ---BT I \ [ \1.20 _._.- COMMERCIAL [ \ [ \ [ \1.00 I \ I \0.80 /I \ \0.60 ~ ".. /1'.1"'/' ".. ...10.40 ".­,- /,-/ / ,-./ 0.20 17 23 30 8 12 20 28 8 22 30 JUNE JULY AUGUST NO.lPLANT ADULTS 2.0 r-------------------------...... I I I I I ._-_. UNTREATED1.5 I I --BT I [ _._.- COMMERCIAL [ [ I ~1.0 [ I I 0.5 ,.. ............1 /i 0.4 / I 0.3 02  ...... ----~-_ // /- .- '. -.... / - .' • ~ 0.1 ..... 8'. e''''-''' ,,,XL ::1~~-~1~7~~23~~~30~~~8==~~12~~2~0~~2~8~~~8~~22~~~30· JUNE JULY AUGUST Fig. 3. Effects on numbers of Colorado pOlato beede 3rd and 4th instar larvae or adults on tomato plants due to \\ ekly applications of Bacillus thuringiensis vaL thuringiensis at a dilution of I: 1000 at Cambridge. 1m. 5Cantwell and Cantelo: Control of the Colorado Potato Beetle (Coleoptera: Chrysomelidae)Published by ValpoScholar, 1984150 THE GREAT LAKES ENTOMOLOGIST Vol. 17, No, 3 Table 2. Percent reduction of the Colorado potato beetle on tomato plants treated with either Bac llus thurillgiellsis var. lhuringiensis (B.t.t.)" or Vydate compared to untreated plants at Cambridge, MD. B.t.t. (I :500) B.t.!. (I: 1000) egg 57.6 0.0 100.0 1st & 2nd instar 34.3 0.0 99.2 3rd & 4th instar 99.1 99.5 98.5 adult 94.8 88.9 94.2 "B.t.t. Experimental preparation of crude supernatant, strain #19 supplied by Biochem Products. LITERATURE CITED Burgerjon, A., G. Biache, and P. Cals. 1969. Teratology of the Colorado potato beetle. Leptinotarsa decemlineata, as provoked by larval administration of the thermostable toxin Bacillus thuringiensis. J. Invertebr. Pathol. 14:274-278. Cantwell, G. E. and W. W. Cantelo. 1981. Bacillus thuringiensis, a potential control agent for the Colorado potato beetle. Amer. Potato 1. 58:457-468. Forgash, A. 1. 1981. Insecticide resistance of the Colorado potato beetle, Leptinotarsa decemlineata (Say). p. 34-46 in 1. H. Lashomb and R. C. Casagrande (eds.). Advances in potato pest management. Hutchinson Ross Pub. Co., Stroudsburg, PA. Schwartz, P. H. and W. Klassen. 1981. Estimate of losses caused by insects and mites to agricultural crops. CRC Handbook of Pest Management in Agriculture. I: 15~77. 6The Great Lakes Entomologist, Vol. 17, No. 3 [1984], Art. 6https://scholar.valpo.edu/tgle/vol17/iss3/6

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Control of the Colorado Potato Beetle (Coleoptera: Chrysomelidae) on Tomatoes with \u3ci\u3eBacillus Thuringiensis\u3c/i\u3e Var. \u3ci\u3eThuringiensis\u3c/i\u3e

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