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Publication #ENY-473

Insect Management for Sweet Potatoes1

S. E. Webb2

Sweet potatoes are widely grown in Florida. In addition to the traditional moist, orange-fleshed varieties, a dry, white-fleshed type, the boniato, is extensively grown in south Florida. Both types are the same species (Ipomoea batatas), however, and their pest problems are similar.

Foliar pests are generally not too difficult to manage and include agromyzid leafminers, sweetpotato whitefly, (also called silverleaf whitefly), and morningglory leafminer, which is a small caterpillar. Armyworms will also feed on foliage. Natural enemies of these pests can be conserved by using pesticides specific for the pest and avoiding broad-spectrum insecticides, if at all possible.

The most serious pests are those whose immature stages feed on roots: sweetpotato weevil, wireworms, banded cucumber beetle, pale-striped and sweetpotato flea beetles, and in south Florida, Diaprepes weevil and Cuban May beetle. Other white grubs will also feed on sweet potato roots. There are very few soil insecticides available at this time. One of the few that remain, chlorpyrifos, has a 125 days-to-harvest interval which rules out its use with early-maturing varieties. Foliar insecticides aimed at the adult stage can give some control.

Sweetpotato weevil is the most serious pest of sweet potatoes (http://edis.ifas.ufl.edu/IN154). Sweet potatoes fed upon by weevil larvae become extremely bitter in taste so even minor feeding renders the potato unmarketable. Some varieties of sweet potato (Regal, for instance) have some resistance to the weevil as well as other beetle pests but the most popular orange-fleshed variety, Beauregard, is highly susceptible. Of varieties currently grown in Florida, Jewel is the only one with some resistance to insects (flea beetles).

In areas of the state where weevils are not common, it is very important to use only certified slips or transplants from weevil-free areas to avoid introducing weevils. The adult weevil does not have wings, and it and the larval stage are most often moved by transporting infested plants or storage roots (potatoes). During the growing season, keeping storage roots covered with soil helps reduce damage by preventing female weevils from laying eggs directly in roots.

Cultural practices can help reduce insect problems. Ideally, soil should be turned two to three months before planting. Crop rotation is also important. Avoid growing sweet potatoes in the same field two years in a row. New fields should be at least a mile from old fields. Destroy crop residues and culls immediately after harvest and for weevils, empty and clean potato storage areas thoroughly at least a month before harvesting the new crop.

The following table lists insecticides currently registered for use on sweet potatoes.

Tables

Table 1. 

Selected insecticides approved for use on insects attacking sweet potatoes.

Trade Name

(Common Name)

Rate

(Product/acre)

REI

(hours)

Days to

Harvest

Insects

MOA

Code1

Notes

Actara

(thiamethoxam)

1.5-3.0 oz

12

14

aphids, flea beetles, potato leafhopper

4A

Toxic to bees. Do not use after Platinum.

Admire Pro

(imidacloprid)

4.4-10.5 fl oz - soil

1.2 fl oz - foliar

12

125 – soil

7 - foliar

aphids, flea beetles, leafhoppers, whiteflies

4A

One application to soil per season. If using as a foliar spray, no more than 3.7 fl oz per acre per season.

Agree WG

(Bacillus thuringiensis subsp. aizawai)

0.5-2.0

4

0

armyworms, hornworms, loopers

11A

Treat when larvae are small.

*Agri-Mek SC

(abamectin)

1.75-3.5 fl oz

12

14

Liriomyza leafminers, spider mites

6

Must be used with a non-ionic activator type wetting, spreading and/or penetrating adjuvant., not a binder sticker type adjuvant.

Assail 30SG

(acetamiprid)

1.5-4.0 oz

12

7

aphids, cucumber beetles, flea beetles, leafhoppers, whiteflies

4A

Whiteflies not on label for sweet potatoes but are for other crops on label. No more than 4 applications per season.

Avaunt

(indoxacarb)

2.5-6.0 oz

12

7

cabbage looper

22

Do not apply more than 24 oz/acre per crop.

Aza-Direct

(azadirachtin)

1-2 pts, up to 3.5 pts, if needed

4

0

aphids, beetles, caterpillars, leafhoppers, leafminers, mites, stink bugs, thrips, weevils, whiteflies

un

Antifeedant, repellant, insect growth regulator. OMRI-listed2.

Azatin XL

(azadirachtin)

5-21 fl oz

4

0

aphids, beetles, caterpillars, leafhoppers, leafminers, thrips, weevils, whiteflies

un

Antifeedant, repellant, insect growth regulator.

*Baythroid XL

(beta-cyfluthrin)

0.8-2.8 fl oz

12

0

cutworms, cabbage looper, flea beetles, potato leafhopper, sweetpotato weevil adults

3A

No more than 16.8 oz/acre per season.

Belay Insecticide

(clothianidin)

in-furrow or side dress: 9-12 fl oz, foliar: 2-3 fl oz

12

foliar: 14

Aphids, corn wireworm, flea beetles, leafhoppers, southern potato wireworm, sweetpotato weevil, tobacco wireworm, white grubs

4A

In-furrow or side-dress application, including chemigation up to 50% ground cover.

Beleaf 50 SG

(flonicamid)

2.0-2.8 oz

12

7

aphids, plant bugs

9C

Do not apply more than 8.4 oz per acre per season.

Biobit HP

(Bacillus thuringiensis subspecies kurstaki)

0.5-2.0 lb

4

0

caterpillars (will not control large armyworms)

11A

Treat when larvae are young. Good coverage is essential. Can be used in the greenhouse. For organic production.

BotaniGard 22 WP, ES

(Beauveria bassiana)

WP: 0.5-2 lb/100 gal

ES: 0.5-2 qt/100/gal

4

0

aphids, thrips, whiteflies

--

May be used in greenhouses. Contact dealer for recommendations if an adjuvant must be used. Not compatible in tank mix with fungicides.

*Brigade 2 EC

(bifenthrin)

9.6-19.2 oz at-plant (soil); 3.2-9.6 oz at lay-by (soil); 2.1-6.4 oz (foliar)

12

21

cucumber beetles, flea beetles, sweetpotato weevil adults (foliar), whitefringed beetle adults, white grub adults, white grubs (lay-by), wireworm adults, wireworms (at-plant and lay-by)

3A

No more than 2 foliar applications, at least 21 days apart. Do not apply more than 0.5 lb active ingredient per acre per season, including soil applications.

Coragen

(rynaxypyr)

3.5-5.0 fl oz

4

1

beet armyworm

28

Foliar only. No more than 4 applications per crop. Do not make more than 2 successive applications in a 30-day period. Do not apply more than 15.4 fl oz per acre per crop.

Crymax WDG

(Bacillus thuringiensis subspecies kurstaki)

0.5-2.0 lb

4

0

caterpillars

11A

Use high rate for armyworms. Treat when larvae are young.

Deliver

(Bacillus thuringiensis subspecies kurstaki)

0.25-1.5 lb

4

0

caterpillars

11A

Use higher rates for armyworms. OMRI-listed2.

Diatect V; Diatect Multipurpose Insecticide II (diatomaceous earth + pyrethrins + piperonyl butoxide)

1-6 lb

12

0

aphids, armyworms, cabbage looper

3A, --

Diatect V is OMRI-listed2 (no piperonyl butoxide)

DiPel DF

(Bacillus thuringiensis subspecies kurstaki)

0.5-2.0 lb

4

0

caterpillars

11A

Treat when larvae are young. Good coverage is essential.

*Endigo ZC

(lambda-cyhalothrin, thiamethoxam)

3.5-4.5 fl oz

24

14

armyworms, blister beetles, corn earworm, crickets, cucumber beetles, cutworms, flea beetles, grasshoppers, leafhoppers, loopers, plant bugs, saltmarsh caterpillar, stink bugs, sweet potato leaf beetle and vine borer, thrips, webworms, whiteflies

3A, 4A

Do not exceed a total of 10 fl oz of product per acre per growing season. Do not use with other Group 4A insecticides.

Entrust SC

(spinosad)

3-10 fl oz

4

7

armyworms, leafminers, Liriomyza, loopers, thrips

5

Do not make applications less than 7 days apart or apply more than 4 times per crop. Do not apply more than 21 fl oz/acre per crop. OMRI-listed2

Esteem Ant Bait

1.5-2.0 lb

12

1

fire ants

7D

Do not exceed a total of 0.109 lb pyriproxyfen per acre (all formulations, i.e., Knack IGR). Ant Bait contains 0.5% ai, or 0.10 lb at 2-lb rate.

(pyriproxyfen)

Extinguish

((S)-methoprene)

1.0-1.5 lb

4

0

fire ants

7A

Slow-acting IGR (insect growth regulator). Best applied early spring and fall where crop will be grown. Colonies will be reduced after three weeks and eliminated after 8 to 10 weeks.

Fulfill

(pymetrozine)

2.75-5.5 oz

12

14

buckthorn aphid, green peach aphid, melon aphid, potato aphid

9B

Allow a minimum of 7 days between applications. Do not exceed 11 oz/acre/season.

Grandevo

(Chromobacterium subtsugae strain PRAA4-1)

1-3 lb

4

0

aphids, armyworms, loopers, potato leafhopper, whiteflies

OMRI-listed2.

Imidan 70 W

(phosmet)

1.3 lb

4 days for seedbed treatment, 5 days for foliar

7

banded cucumber beetle, sweetpotato weevil, whitefringed beetle, suppression of white grub and wireworm

1B

No more than 5 applications per season. Do not apply through irrigation system. Crop must be mechanically harvested.

Javelin WG

(Bacillus thuringiensis subspecies kurstaki)

0.12-1.5 lb

4

0

most caterpillars, but not Spodoptera species (armyworms)

11A

Treat when larvae are young. Thorough coverage is essential. OMRI-listed2.

Lorsban 15G, 75WG, *Advanced

(chlorpyrifos)

See labels for rates

24

preplant broadcast treatment, 125 days before harvest

flea beetles, sweet potato flea beetle, wireworms

(Conoderus)

1B

See label. Must be incorporated into soil.

Malathion 8 F (malathion)

1-1.5 pt

12

3

leafhoppers, morning glory leafminer

1B

Maximum of two applications per year.

*Mocap 15 G, *EC

(ethoprop)

See labels

48

preplant

see label

cucumber beetles, flea beetles, white grubs, wireworms

1B

Two to three weeks before planting.

Movento

(spirotetramat)

4.0-5.0 fl oz

24

7

aphids, psyllids, whiteflies

23

Maximum of 10 fl oz/acre per season.

M-Pede 49% EC

Soap, insecticidal

1-2 % V/V

12

0

aphids

OMRI-listed2.

*Mustang

(zeta-cypermethrin)

1.4-4.3 oz

12

1

cabbage looper, cucumber beetles, cutworms, flea beetles, grasshoppers, leafhoppers, tarnished plant bug, vegetable weevil, whitefringed beetle (adult), yellowstriped armyworm; aids in control of aphids and beet armyworm

3A

A maximum of 0.3 lb ai/acre per season may be applied. Leaves cannot be used for food or feed.

Neemix 4.5

(azadirachtin)

4-16 fl oz

12

0

aphids, beetles, caterpillars, grasshoppers, leafhoppers, leafminers, weevils, whiteflies

un

Does not kill adult insects. IGR and feeding repellant. OMRI-listed2.

Oberon 2SC

(spiromesifen)

8-16 fl oz

12

7

twospotted spider mite, whiteflies

23

Maximum amount per crop: 32 oz/acre. No more than 2 applications.

Oil, insecticidal

1-2 gal/100 gal

12

Up to day of harvest

leafminers, mites, whiteflies

--

 

Platinum

Platinum 75SG

(thiamethoxam)

5-8 fl oz

1.66-2.67 oz

12

Applied at planting

aphids, Colorado potato beetles, flea beetles, potato leafhoppers

4A

For most crops that are not on the label, a 120-day plant-back interval must be observed. To manage resistance, avoid using Actara or Provado in conjunction with Platinum.

Provado 1.6F

(imidacloprid)

3.5 oz

12

7

aphids, flea beetles, leafhoppers, whiteflies

4A

Limited to 3 applications.

Radiant SC

(spinetoram)

6-8 fl oz

4

7

armyworm, Colorado potato beetle, dipterous leafminer, loopers, thrips

5

Do not make more than 4 applications per year.

Rimon 0.83 EC

(novaluron)

6-12 fl oz

12

14

armyworms, loopers, other foliage feeding caterpillars, sweet potato leafminer, whiteflies

15

Do not apply more than 24 oz per acre per season. Limited to two applications for whiteflies (12-oz rate).

Sevin 80S; XLR; 4F

(carbaryl)

80S: 1.25-2.5 lb

XLR, 4F: 1-2 qt

12

7

corn earworm, cucumber beetles, flea beetles, sweetpotato hornworm, sweetpotato weevil (preplant dip), tortoise beetle, whitefringed beetle, yellowstriped armyworm

1A

Do not apply more than 10 lb (80S) per acre per crop or 8 qt (4F, XLR). See label for preplant dip treatment.

Trilogy

(extract of neem oil)

0.5-2.0% V/V

4

0

aphids, mites, suppression of thrips and whiteflies

un

Apply morning or evening to reduce potential for leaf burn. Toxic to bees exposed to direct treatment.

OMRI-listed2.

Voliam Flexi

(thiamethoxam and chlorantraniliprole)

4 oz

12

14

aphids, beet armyworm, cabbage looper, flea beetles, potato leafhopper

4A, 28

Do not exceed a total of 8 oz of product per acre per season.

*Voliam Xpress

(lambda-cyhalothrin and chlorantraniliprole)

5-9 oz

24

14

aphids, armyworms, crickets, cutworms, flea beetle adults, grasshoppers, leafhoppers, loopers, saltmarsh caterpillar, stink bugs, sweet potato vine borer, webworms, others

3A, 28

Do not apply more than 27.0 fl. oz of product per acre per season. Supplemental label.

Xentari DF

(Bacillus thuringiensis subspecies aizawai)

0.5-2.0 lb

4

0

caterpillars

11A

Treat when larvae are young. Thorough coverage is essential. May be used in the greenhouse. Can be used in organic production.

The pesticide information presented in this table was current with federal and state regulations at the time of revision. The user is responsible for determining the intended use is consistent with the label of the product being used. Use pesticides safely. Read and follow label instructions.

1Mode of Action codes for vegetable pest insecticides from the Insecticide Resistance Action Committee (IRAC) Mode ofAction Classification v.7.2 February 2012. http://www.irac-online.org/wp-content/uploads/MoA-classification.pdf

1A. Acetylcholinesterase inhibitors, Carbamates (nerve action)

1B. Acetylcholinesterase inhibitors, Organophosphates (nerve action)

2A. GABA-gated chloride channel antagonists (nerve action)

3A. Sodium channel modulators—pyrethroids

4A. Nicotinic acetylcholine receptor agonists (nerve action)

5. Nicotinic acetylcholine receptor allosteric activators—spinosins (nerve action)

6. Chloride channel activators (nerve and muscle action)

7A. Juvenile hormone mimics (growth regulation)

7C. Juvenile hormone mimics (growth regulation)

9B & 9C. Selective homopteran feeding blockers

10B. Mite growth inhibitors (growth regulation)

11A. Microbial disruptors of insect midgut membranes

12B. Inhibitors of mitochondrial ATP synthase (energy metabolism)

15. Inhibitors of chitin biosynthesis, type 0, lepidopteran (growth regulation)

16. Inhibitors of chitin biosynthesis, type 1, homopteran (growth regulation)

17. Molting disruptor, dipteran (growth regulation)

18. Ecdysone receptor agonists (growth regulation)

20B. Mitochondrial complex III electron transport inhibitors (energy metabolism)

21A. Mitochondrial complex I electron transport inhibitors (energy metabolism)

22. Voltage-dependent sodium channel blockers (nerve action)

23. Inhibitors of acetyl Co-A carboxylase (lipid synthesis, growth regulation)

28. Ryanodine receptor modulators (nerve and muscle action)

un. Compounds of unknown or uncertain mode of action

2OMRI listed: Listed by the Organic Materials Review Institute for use in organic production.

*Restricted Use Only.

Footnotes

1.

This document is ENY-473 (IG159), one of a series of the Entomology & Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published August 2001. Revised March 2010 and June 2013. For more publications related to horticulture/agriculture, please visit the EDIS Wwebsite at http://edis.ifas.ufl.edu/.

2.

S. E. Webb, associate professor, Entomology and Nematology Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611-0640.

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication does not signify our approval to the exclusion of other products of suitable composition. All chemicals should be used in accordance with directions on the manufacturer's label. Use pesticides safely. Read and follow directions on the manufacturer's label.


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U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.