Who dunnit? Voles or Pocket Gophers?

By Irene Shonle, CSU Extension in Gilpin County

There are many burrowing animals in Colorado that can cause damage to lawns, gardens, and pastures. The first step to resolving the problem is to figure out which animal (or animals) caused the damage.

The main four types of burrowing animals are voles (8 species), pocket gophers (4 species), prairie dogs, and Wyoming ground squirrel.   Moles are rarely found in Colorado, and only in the very eastern plains.  If you are outside that area, the species causing damage is one of the other four.

  In this post, I'll just be discussing the difference between voles and pocket gophers, since these are the critters I most often deal with in the mountains.

Voles

This year has been a very bad year for voles.

Voles cause several types of damage.  They gnaw on bark of trees and shrubs, sometimes girdling it entirely and causing the death of trees. Most damage occurs in the winter when voles move through their grass runways under the protection of snow. The greatest damage seems to coincide with years of heavy snowfall.

Vole damage to trees and shrubs is characterized by girdling and patches of irregular patterns of gnaw marks about 1/16 to 1/8-inch wide. Gnawed stems may have a pointed tip.

Other signs of damage by voles include: 1- to 2-inch-wide runways through matted grass with open 1-2 inch holes and spongy soil from burrowing activity. 

It is common to see voles, as they are active all year round, and are frequently above ground.

Vole damage on lilac. Notice small, irregular tooth marks, all under what was the snow line.

 

Vole trails in lawn after snow melted in spring

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Vole hole and trail in clay soil

Vole hole and trail in snow.  Note the oval-shaped OPEN hole

Examples of vole holes.  

They will often burrow near a rock, but not always.

Pocket gophers

Pocket gophers rarely appear above ground, spending most of their lives in burrows.  Prairie dogs and Wyoming ground squirrels, on the other hand, are frequently seen above ground.

The mounds that pocket gophers create are fan-shaped to round and usually have closed entrances, unlike prairie dogs and Wyoming ground squirrels. 

The main signs of damage from pocket gophers include mounds of soil (with no apparent hole), eskers (solid tubes of soil) above ground when the snow melts in the spring, and suddenly wilting plants (due to root damage).   If you walk across an area inhabited by pocket gophers, your foot will frequently break through into their tunnels.  The tunnels are usually 2.5-3.5” in diameter, and are usually found in the top 4-18” of soil.

An example of an esker - these solid soil tubes are only seen as the snow melts, and are a result of burrowing activity in the snow.

Fan-shaped mound with closed hole is typical of pocket gophers in the summer

 Now that you have a good idea of who dunnit, please refer to the following fact sheets for help with dealing with them:  6.507 Managing Voles in Colorado, 6.515 Managing Pocket Gophers.

A Pain in the Ascochyta!

Tony Koski, Extension Turf Specialist

Ascochyta leaf blight has blown up across the state – on home lawns, sports turf and even golf courses. This disease occurs most frequently and severely when we abruptly transition from a cool, wet spring to hot, dry summer conditions. Perfectly healthy green grass develops random straw-colored blotchy patches and streaks. Brown wheel tracks from the operation of mowers and other maintenance equipment often appear, leading some to believe (incorrectly) that
equipment is tracking the fungus onto the turf. The wheel-marking occurs when wilted, drought/heat-stressed grass leaves are crushed by the wheels of heavy mowers as they move across the turf. The browning in the wheel tracks is caused by a combination of direct leaf injury (crushing) and Ascochyta occurring in the stressed turf. The wheel-marking is NOT the result of the disease organism being tracked onto the lawn from somewhere else.

The good news with this disease is that, while the turf appears dead, it will recover within a few weeks. The fungus attacks leaves (through the mowed leaf tip), but rarely kills the crown or roots. Affected grass plants must produce new leaves to replace the dead ones, a process that may take 10 days to 3 weeks depending on severity of the outbreak and species of grass affected. More rapidly growing grasses like tall fescue and perennial ryegrass will recover more quickly than will the slower-growing bluegrasses and fine fescues.

The most spectacular outbreaks occur where the turf manager or homeowner has delayed firing up the irrigation system (perhaps with the thought that “it has rained all spring, so I don’t need to begin watering yet”) or where irrigation coverage is poor due to a broken head or other system malfunction. While death by Ascochyta is uncommon, failure to repair the coverage issue or provide adequate irrigation may cause turf death that will be attributed to the disease.

Fungicides are not recommended for this disease. In fact, few fungicides will have Ascochyta on their label. Repairing the irrigation coverage problem – or beginning appropriate irrigation – will begin the recovery process. Avoid the temptation to irrigate recovering turf excessively, as saturated soil may result in other problems (weeds, other disease activity). 

Happily, once turf has recovered from an Ascochyta outbreak, the disease will generally not reappear again in the same season. While a true turf disease, an outbreak of Ascochyta almost always arises because of poor water management by the homeowner or turf manager.