Sep 30, 2021

Vole control: How to reduce damage to orchards

{Sponsored} Of all the pests that can plague an orchard, voles can cause a significant amount of damage before growers even know there’s a problem — and by the time they realize there is, it may be too late to salvage injured trees. 

Damage caused by voles, including girdling and root destruction, can cause apple or stone fruit trees to become sickly and less productive, leading to a reduction in yield and possible loss of trees. It’s important that this pest is well-controlled to maximize the orchard’s useful life and ROI. But for many, that’s a tall task. 

Voles overwinter in orchard blocks or adjacent wild areas, feeding on roots and girdling them, stopping them from being able to absorb nutrients; they tunnel through snow and are capable of girdling trunks up to the snow line as well, creating a nasty surprise in the spring. 

Overcoming this prolifically reproducing pest requires preventative actions including monthly monitoring via bait stations, plus corrective measures to reduce infestations. Investing in the right program to rid the orchard of these meddlesome pests is a major step in preventing unrecoverable vole damage — as well as one that can save growers significant money in lost yields and replacing critically damaged trees. 

In orchards where polyculture is present, and especially when grapevines are interspersed with fruit trees, this issue becomes even more dangerous; the cover crops and weeds often found in vineyards can harbor voles and allow the populations to build to an untenable level. 

As a result, it’s imperative that growers are proactive in reducing vole pressure. This includes applying several key integrated pest management (IPM) strategies and incorporating a baiting program to rout out the varmints. 

Simple IPM strategies that can help reduce vole pressure include creating vegetation-free zones in two feet in every direction from trunks, removing grass or weed harborage, and protecting the lower trunks of young trees with tree guards (where cost-justifiable). 

Along with these strategies, growers need to bait for voles to ensure that there will not be an issue. This preventative type of program will help growers monitor and reduce breeding populations in the orchard. 

Bait programs are done in one of two ways: either with two fall applications or with a fall and a spring application. According to Greg Newman, chief agronomist at NWFM, LLC, a sustainability-first farm management service provider, a spring and fall bait application tends to work best in most situations, but in some cases, two fall applications will be necessary instead to eradicate an especially tenacious population. 

Regardless which strategy growers choose around timing of bait programs, these are the essential steps that should be taken to ensure those programs significantly reduce nearby voles. 

Baiting Methodology

1. Reducing harborage / clearing fruit: when the majority of fruit is harvested, clear any left on the ground. While voles primarily feed on bark and roots, they will be attracted to migrate into and remain longer in the orchard if excessive fruit is easily accessible. 
2. Choose the right bait: with Rozol® Vole Bait from Liphatech, “You definitely see the results after several days,” Newman said. He uses Rozol bait for a variety of orchards at different levels of maturity. 
3. Bait station monitoring: Using perimeter (inverted T-pipe) bait stations, placing bait and checking frequently to see if it is disappearing. For bait stations placed within the fruit block, move them around to a new location if bait is untouched, and place at higher densities (minimum one per acre) if vole pressure is high. 
4. Protect the perimeter: Broadcast bait around crop / fruit borders when high vole pressure is observed. 
5. Repeat application if needed: when excessive vole presence warrants it, do a second Fall or Spring in dormant orchard application according to label instructions. 

A twice-yearly Rozol Vole Bait program, applied for 10 years, costs less per acre than replacing the lost production from a single tree. The level of vole population reduction provided by Rozol Vole Bait was confirmed in an independent study (completed by Qualls Agricultural Lab in Ephrata, WA); the study found that Rozol Vole Bait reduces populations by 80% and feeding by 62% (compared to 3% in untreated areas). 

About Rozol Vole Bait, a restricted use pesticide 

Rozol Vole Bait contains the active ingredient chlorophacinone and is formulated as paraffinized pellets for effective control, weatherability and palatability. Chlorophacinone is a multi-feed anticoagulant invented by Liphatech and used for over 50 years. Moisture-resistant Rozol Vole Bait reduces the chances of tree and root girdling, runway damage and production losses from voles on your property. 

To learn more about Rozol Vole Bait and to get a discount on your next Rozol order, visit liphatech.com/agriculture. 

Rozol® Vole Bait is a registered trademark of Liphatech, Inc. Rozol is a restricted use pesticide. 

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