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well in advance of baiting time. Over a period of weeks or months voles 

 develop trails under these bait stations — trails that can be baited quickly 

 after harvest. 



Orchard Floor Sprays . Liquid Rozol^^ (chlorphacinone) is an anticoagulant 

 formulated for spray application. In order for it to be effective, it must 

 thoroughly wet and penetrate the ground cover. Before the spray is applied, 

 the ground cover should be dry and mown short enough for maximum penetration. 

 Voles are killed after repeated exposure to residues on the ground and cover 

 crop. Liquid Rozol will not be effective when there is no surface-feeding 

 activity. 



Estimating Vole Activity 



Vole activity can be estimated by placing apples in runways or tunnel 

 entrances. Place whole, firm apples, with a thin slice removed, at regular 

 intervals throughout the orchard where activity is suspected. After 24 hours, 

 look for small teeth marks in the apples. If such a check indicates voles are 

 present 2 to 3 weeks following a baiting, a second treatment may be needed. 



Re-treatment with Baits 



Where some voles have been sickened by a rodenticide treatment but have 

 survived, the acceptance of the same bait a second time within a few weeks will 

 be poor. This problem seems to be more common with zinc phosphide baits than 

 with anticoagulants. If a second treatment is needed, use a different bait 

 (e.g., if zinc phosphide was used in the earlier treatment, use an 

 anticoagulant for the follow-up). Obviously, the best way to deal with this 

 problem is to prevent it from occurring: do everything possible to kill all of 

 the voles with the first treatment. 



Orchard Borders 



In the brushy areas immediately adjacent to a vole-infested orchard, one 

 can generally find a relatively high population of the same species that is 

 present in the orchard. If these border areas are not baited, they will be a 

 source of reinfestation of the treated orchard. 



Caution 



Rodenticide baits may be attractive to domestic pets, wild birds, and 

 other nontarget wildlife. Exposed bait, and especially exposed piled bait, 

 increases the chances of nontarget injury. As with all pesticides, use good 

 judgment and take reasonable precautions to avoid problems. 



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