Grape growers in California lose between three and four million dollars annually from damage caused principally by two bird species: Linnets (carpodacus mexicanus) and Starlings (sturnus vulgaris) (DeHaven, 1974; Crase, et al., 1975),. Few effective tools exist for the growers to use in reducing crop losses from bird damage; and current bio-political trends may preclude the use of toxicants to control local depredating bird populations, especially Linnets. The use of chemical repellents is a possible alternative.  Testing of the chemical repellent methiocarb [3,5-dimethyl-4-(methylthio) phenol methylcarbamate] to protect California wine grapes has been conducted by Denver Wildlife Research Center personnel (Guarino, 1972; DeHaven, 1974; Crase, et al., 1975; and Crase & DeHaven, 1976). Results with methiocarb on grapes appear successful on a small scale. Other researchers (Stone & Toms, 1970) investigated a compound called CURB, aluminum am- monium sulfate, and obtained limited success when used on vegetable, cereal, and fruit crops including grapes. Leinati (1968) used CURB as a seed dressing to reduce seedling pulling by pheasants. Dar (1974) completed a series of trials at eight different Israeli agricultural stations, using CURB on seedling sugar beets, cucumbers, radishes, lettuce, celery, beans, kohlrabi, and strawberries. Data indicate that CURB provides good protection for plants with large leaf surface area, but results of trials to reduce seedling pulling by birds varied too much for valid conclusions. Trials on legumes raised for seed and sorghum were encouraging.  Tests with CURB-treated wine grapes in Australia and South Africa have yielded inconclusive results about its effectiveness as an avian repellent. In Israel, specialists indicate that the metallic salts of CURB affect wine flavor (Stone, 1976). Although test results with CURB appear variable and inconclusive, General Vineyard Services in Salinas Valley, California, offered grape acreage for test plots to evaluate the potential of CURB as an avian repellent. This paper reports on preliminary cage and field trials

Crabb, A. Charles

Ewing, Ken

Martin, Lee R.

Moitoso, Roger

English

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University of Nebraska - Lincoln 
DigitalCommons@University of Nebraska - Lincoln 
Bird Control Seminars Proceedings Wildlife Damage Management, Internet Center for 
November 1976 
PRELIMINARY LABORATORY AND FIELD TRIALS OF CURB, A 
POSSIBLE AVIAN REPELLENT 
Ken Ewing 
Monterey County Department of Agriculture, Salinas, California 
A. Charles Crabb 
Institute of Ecology, University of California, Davis, California 
Lee R. Martin 
California Department of Food and Agriculture, Fresno 
Roger Moitoso 
General Vineyard Services, Gonzales, California 
Follow this and additional works at: https://digitalcommons.unl.edu/icwdmbirdcontrol 
 Part of the Environmental Sciences Commons 
Ewing, Ken; Crabb, A. Charles; Martin, Lee R.; and Moitoso, Roger, "PRELIMINARY LABORATORY AND 
FIELD TRIALS OF CURB, A POSSIBLE AVIAN REPELLENT" (1976). Bird Control Seminars Proceedings. 76. 
https://digitalcommons.unl.edu/icwdmbirdcontrol/76 
This Article is brought to you for free and open access by the Wildlife Damage Management, Internet Center for at 
DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Bird Control Seminars 
Proceedings by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. 
239
PRELIMINARY LABORATORY AND FIELD TRIALS OF CURB,
A POSSIBLE AVIAN REPELLENT
Ken Ewing
Monterey County Department of Agriculture
Salinas, California
A. Charles Crabb
Institute of Ecology, University of California
Davis, California
Lee R. Martin
California Department of Food and Agriculture
Fresno, California
and
Roger Moitoso
General Vineyard services
Gonzales, California
Grape growers in California lose between three and four million dollars annually from
damage caused principally by two bird species: Linnets (carpodacus mexicanus) and Star-
lings (sturnus vulgaris) (DeHaven, 1974; Crase, et al., 1975),. Few effective tools exist
for the growers to use in reducing crop losses from bird damage; and current bio-political
trends may preclude the use of toxicants to control local depredating bird populations,
especially Linnets. The use of chemical repellents is a possible alternative.
Testing of the chemical repellent methiocarb [3,5-dimethyl-4-(methylthio) phenol
methylcarbamate] to protect California wine grapes has been conducted by Denver Wildlife
Research Center personnel (Guarino, 1972; DeHaven, 1974; Crase, et al., 1975; and Crase &
DeHaven, 1976). Results with methiocarb on grapes appear successful on a small scale.
Other researchers (Stone & Toms, 1970) investigated a compound called CURB, aluminum am-
monium sulfate, and obtained limited success when used on vegetable, cereal, and fruit
crops including grapes. Leinati (1968) used CURB as a seed dressing to reduce seedling
pulling by pheasants. Dar (1974) completed a series of trials at eight different Israeli
agricultural stations, using CURB on seedling sugar beets, cucumbers, radishes, lettuce,
celery, beans, kohlrabi, and strawberries. Data indicate that CURB provides good pro-
tection for plants with large leaf surface area, but results of trials to reduce seedling
pulling by birds varied too much for valid conclusions. Trials on legumes raised for
seed and sorghum were encouraging.
Tests with CURB-treated wine grapes in Australia and South Africa have yielded in- 
conclusive results about its effectiveness as an avian repellent. In Israel, specialists
indicate that the metallic salts of CURB affect wine flavor (Stone, 1976). Although test
results with CURB appear variable and inconclusive, General Vineyard Services in Salinas
Valley, California, offered grape acreage for test plots to evaluate the potential of
CURB as an avian repellent. This paper reports on preliminary cage and field trials.
CAGE TRIALS
Methods and Materials
Trials conducted with caged birds were based on methods similar to those of Crase
and DeHaven (1976) for evaluating chemical repellents on grapes. Twelve cages 6' x 10'
were used. Ten Starlings were put into each of six cages, and ten Linnets were put into
each of the remaining six cages. Grapes were treated by dipping them for 30 seconds into
a solution of one pound of CURB to two gallons of water. Two treated grape bunches and
two untreated control bunches of approximately the same size were suspended by strings in 
each of the cages for eight hours. Water and an alternate food source were provided ad
libitum during the exposure period. Damage was determined by counting the number of grapes
damaged or missing from the bunch compared with the total number of grapes originally on
the bunch.
Results
Table 1 lists results from the six cages containing Starlings. Percent damage on
the treated grapes ranged from 10 to 100 percent, with a mean damage value of 66.8 percent.
Damage to control (untreated) grapes ranged from 88 to 100 percent, with a mean of 94.5
percent. Damage on the treated grapes was significantly lower (P < 0.001) than the con-
trol grapes, based on the t-test.
240
Table 2 indicates the effectiveness of CURB in repelling Linnets. Linnet damage to
the treated grapes ranged from 30 to 100 percent, with a mean of 52.5 percent. Damage to
control grapes ranged from 50 to 100 percent, with a mean of 82.5 percent. Damage on the
treated grapes was significantly lower than on the control grapes (P < 0.05).
FIELD TRIALS
Methods and Materials
A block of Gamay Beaujolais grapes was used for the study. Ground spray equipment
was used to apply CURB plus 0.5% adhesive agent at a 30 pounds per acre rate to a one
half-acre plot. The grapes were harvested by hand two weeks after treatment. Treated
and untreated grapes were given to the Paul Masson Winery staff for processing. Sample
batches of wine were made from treated and untreated grapes to determine if CURB would
affect wine flavor. Three batches were produced, the first from treated grapes, the
second from treated grapes that were washed after harvest; the third batch was from un-
treated grapes from the same block.
Results
Professional wine tasters reported that wine produced from the treated and the treat-
ed-washed grapes tasted the same. Both had a subtle, metallic flavor and a lower than
normal pH, a condition that wine producers try to avoid. The wine tasters did not judge
the wine unfavorable, however, and will allow the wine to age before further tests. The
wine produced from untreated grapes was considered typical for the grape varietal.
Conclusions
Under these limited, short-term trials, there appears to be some reduction in bird
damage to grapes treated with CURB. A solution of one pound of CURB to two gallons of
water seems to be more effective in repelling Linnets than Starlings. CURB imparts a
subtle, metallic flavor to wine and increases wine acidity at the 30 pounds per acre app-
lication rate. Further taste tests will attempt to determine if CURB-treated grapes will
be acceptable for making wine. If so, further testing will be needed to determine con-
centrations needed to repel Linnets and Starlings and to determine the minimum applica-
tion rate necessary for the chemical to be effective over extended periods.
ACKNOWLEDGEMENTS
We thank the Monterey County Grape Growers Association, General Vineyard Services,
Paul Masson Vineyards, the County Agricultural Commissioner, and Coastal Ag-Chem for their
generosity and assistance in making this study possible. We also thank Dr. Dale Wade for
his comments during the writing of this manuscript.
LITERATURE CITED
Crase, F.T., and R.W. DeHaven. 1976. A cage test for the evaluation of House Finch re-
pellents for grapes, ASTM Vert. Pest Conf. Symposium Proceedings, Monterey, Cali-
fornia. In press.
Crase, F.T., C.P. Stone, R.W. De Haven, and D.F. Mott. 1975. Bird damage to grapes in
the United States with emphasis on California. U.S. Fish and Wildl. Serv. Special
Report (In press).
Dar, G. 1974. Summary of trials with CURB on cultivated vegetables and fruit from sowing
to harvest. Summary of trials with CURB on seedling plant: Legumes and sorghum in
Israel. Assia Maabarot Ltd., 75 derech Haifa, P.O.B. 21141, 61210 Tel-aviv, Israel
(personal communication).
DeHaven, R.W. 1974. Bird damage to wine grapes in Central California, 1973. Proc. Sixth
Vert. Pest Conf. 248-252.
Guarino, J.L. 1972. Methiocarb, a chemical bird repellent: A review of its effective-
ness on crops. Proc. Fifth Vert. Pest Conf. 108-111.
Leinati, L. 1968. Contribution to the knowledge of repellents against game birds. XXII
Congress of the Italian Society of Veterinary Science, Grado, Italy, Sept. 26-29:3.
Stone, R.J. 1976. Shere Laboratories, 1 & 2 Onlow Mews West, London SW7 3AA, England
(personal communication).
Stone, R.J., and A.M. Toms. 1970. The assessment and evaluation of a bird and mammal re-
pellent. 7th Nat'l. Congress of Plant Protection, Paris, France, Sept. 21-25 6pp.
241
TABLE 1. The damage by Starlings to CURB-treated and control
bunches of grapes in each of six cages.
TABLE 2. The percent damage by Linnets to CURB-treated and
control bunches of grapes in each of six cages.


PRELIMINARY LABORATORY AND FIELD TRIALS OF CURB, A POSSIBLE AVIAN REPELLENT

DigitalCommons@University of Nebraska

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Bird Control Seminars Proceedings Wildlife Damage Management, Internet Center for November 1976 PRELIMINARY LABORATORY AND FIELD TRIALS OF CURB, A POSSIBLE AVIAN REPELLENT Ken Ewing Monterey County Department of Agriculture, Salinas, California A. Charles Crabb Institute of Ecology, University of California, Davis, California Lee R. Martin California Department of Food and Agriculture, Fresno Roger Moitoso General Vineyard Services, Gonzales, California Follow this and additional works at: https://digitalcommons.unl.edu/icwdmbirdcontrol  Part of the Environmental Sciences Commons Ewing, Ken; Crabb, A. Charles; Martin, Lee R.; and Moitoso, Roger, "PRELIMINARY LABORATORY AND FIELD TRIALS OF CURB, A POSSIBLE AVIAN REPELLENT" (1976). Bird Control Seminars Proceedings. 76. https://digitalcommons.unl.edu/icwdmbirdcontrol/76 This Article is brought to you for free and open access by the Wildlife Damage Management, Internet Center for at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Bird Control Seminars Proceedings by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. 239PRELIMINARY LABORATORY AND FIELD TRIALS OF CURB,A POSSIBLE AVIAN REPELLENTKen EwingMonterey County Department of AgricultureSalinas, CaliforniaA. Charles CrabbInstitute of Ecology, University of CaliforniaDavis, CaliforniaLee R. MartinCalifornia Department of Food and AgricultureFresno, CaliforniaandRoger MoitosoGeneral Vineyard servicesGonzales, CaliforniaGrape growers in California lose between three and four million dollars annually fromdamage caused principally by two bird species: Linnets (carpodacus mexicanus) and Star-lings (sturnus vulgaris) (DeHaven, 1974; Crase, et al., 1975),. Few effective tools existfor the growers to use in reducing crop losses from bird damage; and current bio-politicaltrends may preclude the use of toxicants to control local depredating bird populations,especially Linnets. The use of chemical repellents is a possible alternative.Testing of the chemical repellent methiocarb [3,5-dimethyl-4-(methylthio) phenolmethylcarbamate] to protect California wine grapes has been conducted by Denver WildlifeResearch Center personnel (Guarino, 1972; DeHaven, 1974; Crase, et al., 1975; and Crase &DeHaven, 1976). Results with methiocarb on grapes appear successful on a small scale.Other researchers (Stone & Toms, 1970) investigated a compound called CURB, aluminum am-monium sulfate, and obtained limited success when used on vegetable, cereal, and fruitcrops including grapes. Leinati (1968) used CURB as a seed dressing to reduce seedlingpulling by pheasants. Dar (1974) completed a series of trials at eight different Israeliagricultural stations, using CURB on seedling sugar beets, cucumbers, radishes, lettuce,celery, beans, kohlrabi, and strawberries. Data indicate that CURB provides good pro-tection for plants with large leaf surface area, but results of trials to reduce seedlingpulling by birds varied too much for valid conclusions. Trials on legumes raised forseed and sorghum were encouraging.Tests with CURB-treated wine grapes in Australia and South Africa have yielded in- conclusive results about its effectiveness as an avian repellent. In Israel, specialistsindicate that the metallic salts of CURB affect wine flavor (Stone, 1976). Although testresults with CURB appear variable and inconclusive, General Vineyard Services in SalinasValley, California, offered grape acreage for test plots to evaluate the potential ofCURB as an avian repellent. This paper reports on preliminary cage and field trials.CAGE TRIALSMethods and MaterialsTrials conducted with caged birds were based on methods similar to those of Craseand DeHaven (1976) for evaluating chemical repellents on grapes. Twelve cages 6' x 10'were used. Ten Starlings were put into each of six cages, and ten Linnets were put intoeach of the remaining six cages. Grapes were treated by dipping them for 30 seconds intoa solution of one pound of CURB to two gallons of water. Two treated grape bunches andtwo untreated control bunches of approximately the same size were suspended by strings in each of the cages for eight hours. Water and an alternate food source were provided adlibitum during the exposure period. Damage was determined by counting the number of grapesdamaged or missing from the bunch compared with the total number of grapes originally onthe bunch.ResultsTable 1 lists results from the six cages containing Starlings. Percent damage onthe treated grapes ranged from 10 to 100 percent, with a mean damage value of 66.8 percent.Damage to control (untreated) grapes ranged from 88 to 100 percent, with a mean of 94.5percent. Damage on the treated grapes was significantly lower (P < 0.001) than the con-trol grapes, based on the t-test.240Table 2 indicates the effectiveness of CURB in repelling Linnets. Linnet damage tothe treated grapes ranged from 30 to 100 percent, with a mean of 52.5 percent. Damage tocontrol grapes ranged from 50 to 100 percent, with a mean of 82.5 percent. Damage on thetreated grapes was significantly lower than on the control grapes (P < 0.05).FIELD TRIALSMethods and MaterialsA block of Gamay Beaujolais grapes was used for the study. Ground spray equipmentwas used to apply CURB plus 0.5% adhesive agent at a 30 pounds per acre rate to a onehalf-acre plot. The grapes were harvested by hand two weeks after treatment. Treatedand untreated grapes were given to the Paul Masson Winery staff for processing. Samplebatches of wine were made from treated and untreated grapes to determine if CURB wouldaffect wine flavor. Three batches were produced, the first from treated grapes, thesecond from treated grapes that were washed after harvest; the third batch was from un-treated grapes from the same block.ResultsProfessional wine tasters reported that wine produced from the treated and the treat-ed-washed grapes tasted the same. Both had a subtle, metallic flavor and a lower thannormal pH, a condition that wine producers try to avoid. The wine tasters did not judgethe wine unfavorable, however, and will allow the wine to age before further tests. Thewine produced from untreated grapes was considered typical for the grape varietal.ConclusionsUnder these limited, short-term trials, there appears to be some reduction in birddamage to grapes treated with CURB. A solution of one pound of CURB to two gallons ofwater seems to be more effective in repelling Linnets than Starlings. CURB imparts asubtle, metallic flavor to wine and increases wine acidity at the 30 pounds per acre app-lication rate. Further taste tests will attempt to determine if CURB-treated grapes willbe acceptable for making wine. If so, further testing will be needed to determine con-centrations needed to repel Linnets and Starlings and to determine the minimum applica-tion rate necessary for the chemical to be effective over extended periods.ACKNOWLEDGEMENTSWe thank the Monterey County Grape Growers Association, General Vineyard Services,Paul Masson Vineyards, the County Agricultural Commissioner, and Coastal Ag-Chem for theirgenerosity and assistance in making this study possible. We also thank Dr. Dale Wade forhis comments during the writing of this manuscript.LITERATURE CITEDCrase, F.T., and R.W. DeHaven. 1976. A cage test for the evaluation of House Finch re-pellents for grapes, ASTM Vert. Pest Conf. Symposium Proceedings, Monterey, Cali-fornia. In press.Crase, F.T., C.P. Stone, R.W. De Haven, and D.F. Mott. 1975. Bird damage to grapes inthe United States with emphasis on California. U.S. Fish and Wildl. Serv. SpecialReport (In press).Dar, G. 1974. Summary of trials with CURB on cultivated vegetables and fruit from sowingto harvest. Summary of trials with CURB on seedling plant: Legumes and sorghum inIsrael. Assia Maabarot Ltd., 75 derech Haifa, P.O.B. 21141, 61210 Tel-aviv, Israel(personal communication).DeHaven, R.W. 1974. Bird damage to wine grapes in Central California, 1973. Proc. SixthVert. Pest Conf. 248-252.Guarino, J.L. 1972. Methiocarb, a chemical bird repellent: A review of its effective-ness on crops. Proc. Fifth Vert. Pest Conf. 108-111.Leinati, L. 1968. Contribution to the knowledge of repellents against game birds. XXIICongress of the Italian Society of Veterinary Science, Grado, Italy, Sept. 26-29:3.Stone, R.J. 1976. Shere Laboratories, 1 & 2 Onlow Mews West, London SW7 3AA, England(personal communication).Stone, R.J., and A.M. Toms. 1970. The assessment and evaluation of a bird and mammal re-pellent. 7th Nat'l. Congress of Plant Protection, Paris, France, Sept. 21-25 6pp.241TABLE 1. The damage by Starlings to CURB-treated and controlbunches of grapes in each of six cages.TABLE 2. The percent damage by Linnets to CURB-treated andcontrol bunches of grapes in each of six cages.

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