Table 8. Chemical control of alfalfa insects

Table 8. Chemical control of alfalfa insects

Insecticide Pounds Active Ingredient/A fl. oz. product Timing of Treatment and Limitations

Alfalfa weevil Treat when 30-50% of alfalfa tips show some injury, or if tall enough, harvest and treat stubble as needed. Follow 2d stubble application in 7-10 days if necessary. Do not treat during bloom.

First cutting or stubble treatment Before first cutting: Treat when 40% of alfalfa tips show some injury or, if tall enough, harvest. Treat stubble as needed. See text. Follow second stubble application in 7-10 days if necessary. Do not treat during bloom.

cyfluthrin (Baythroid) 0.025-0.044 1.6-2.8 One application per cutting. A total of 11.2 fl. oz. per acre may be applied per season. Wait 7 days after application before harvest.

*carbofuran (*Furadan 4F) 0.125 4 Highly toxic to humans. Use only once per cutting. Wait 14 days before harvest. Avoid applications to fields in bloom. Foliar application. Consult the label.

chlorpyrifos (Lorsban 4E) 0.5 16 Use only once per crop cutting. Wait 14 days before harvest. Foliar application.

lambda-cyhalothin (Warrior T) 0.02-0.03 2.56-3.84 10-15 gallons per acre by ground. Required for good coverage. Do not apply more than 0.03 lb. ai per cutting. Do not apply within 1 day of harvest for forage or 7 days of harvest for hay.

*permethrin (*Ambush, *Pounce) 0.1 No preharvest interval (0 days). At this rate, weevils stop feeding but do not die for 4-7 days. Consult the label.

0.15-0.20 Do not apply more than once per cutting. Wait 14 days before harvest or feeding. Consult the label.

Potato leafhopper Treat as recommended in text.

cyfluthrin (Baythroid) 0.0125-0.025 0.8-1.6 One application per cutting. A total of 11.2 fl. oz. per acre may be applied per season. Wait 7 days after application before harvest.

chlorpyrifos (Lorsban 4E) 0.5 16 Use only once per crop cutting. Wait 14 days (0.5 ai/A) or 21 days (1.0 ai/A) before harvest. Foliar application. Consult the label.

dimethoate 0.25-0.5 Make only 1 application per cutting. Must wait 10 days before feeding or harvesting. Do not apply to alfalfa in bloom. Foliar application. Consult the label.

lambda-cyhalothrin (Warrior T) 0.010-0.025 1.28-3.2 oz. 10-15 gallons per acre by ground. Required for good coverage. Do not apply more than 0.03 lb. ai per cutting. Do not apply within 1 day of harvest for forage or 7 days of harvest for hay.

*permethrin (*Ambush, *Pounce) 0.1-0.2 Do not apply more than once per cutting. If rates are greater than 0.1 lb. ai/A, then wait 14 days before harvest or feeding. If rates are 0.1 lb. ai/A or less, then crop can be harvested immediately. Consult the label.

*Restricted-use pesticide

Insecticide	Pounds Active Ingredient/A	fl. oz. product	Timing of Treatment and Limitations
Alfalfa weevil			Treat when 30-50% of alfalfa tips show some injury, or if tall enough, harvest and treat stubble as needed. Follow 2d stubble application in 7-10 days if necessary. Do not treat during bloom.
	First cutting or stubble treatment		Before first cutting: Treat when 40% of alfalfa tips show some injury or, if tall enough, harvest. Treat stubble as needed. See text. Follow second stubble application in 7-10 days if necessary. Do not treat during bloom.
cyfluthrin (Baythroid)	0.025-0.044	1.6-2.8	One application per cutting. A total of 11.2 fl. oz. per acre may be applied per season. Wait 7 days after application before harvest.
carbofuran (Furadan 4F)	0.125	4	Highly toxic to humans. Use only once per cutting. Wait 14 days before harvest. Avoid applications to fields in bloom. Foliar application. Consult the label.
chlorpyrifos (Lorsban 4E)	0.5	16	Use only once per crop cutting. Wait 14 days before harvest. Foliar application.
lambda-cyhalothin (Warrior T)	0.02-0.03	2.56-3.84	10-15 gallons per acre by ground. Required for good coverage. Do not apply more than 0.03 lb. ai per cutting. Do not apply within 1 day of harvest for forage or 7 days of harvest for hay.
permethrin (Ambush, *Pounce)	0.1		No preharvest interval (0 days). At this rate, weevils stop feeding but do not die for 4-7 days. Consult the label.
	0.15-0.20		Do not apply more than once per cutting. Wait 14 days before harvest or feeding. Consult the label.
Potato leafhopper			Treat as recommended in text.
cyfluthrin (Baythroid)	0.0125-0.025	0.8-1.6	One application per cutting. A total of 11.2 fl. oz. per acre may be applied per season. Wait 7 days after application before harvest.
chlorpyrifos (Lorsban 4E)	0.5	16	Use only once per crop cutting. Wait 14 days (0.5 ai/A) or 21 days (1.0 ai/A) before harvest. Foliar application. Consult the label.
dimethoate	0.25-0.5		Make only 1 application per cutting. Must wait 10 days before feeding or harvesting. Do not apply to alfalfa in bloom. Foliar application. Consult the label.
lambda-cyhalothrin (Warrior T)	0.010-0.025	1.28-3.2 oz.	10-15 gallons per acre by ground. Required for good coverage. Do not apply more than 0.03 lb. ai per cutting. Do not apply within 1 day of harvest for forage or 7 days of harvest for hay.
permethrin (Ambush, *Pounce)	0.1-0.2		Do not apply more than once per cutting. If rates are greater than 0.1 lb. ai/A, then wait 14 days before harvest or feeding. If rates are 0.1 lb. ai/A or less, then crop can be harvested immediately. Consult the label.