Diseases:

Recently scorch has been seen in field and container plantings. Scorch is an abiotic disease meaning it is a result of environmental conditions, not pathogens.

Scorch is typically caused by a lack of water reaching the leaves. This often happens during dry periods or during very hot, sunny weather but can happen anytime water doesn't get to the leaves, such as when there is a canker. Surprisingly, scorch also happens when plants are overwatered. This is because a saturated soil has no oxygen, which is necessary for water uptake.

Scorch symptoms consist of dried areas between veins and on the edges of the leaves. These areas brown first since they are furthest from the water supply - the veins. Upper branches are often prominently affected.

What can you do about it?
Providing irrigation and locating susceptible trees in moisture retentive soils should help prevent scorch.

Source: U.K. Pub. ID-51, Environmental Stress Affecting Woody Ornamentals.

Cultural:

Voles
Several nurseries visited recently have signs of voles. Voles can be a problem in container and field nurseries. Pine voles do most of the below ground damage, feeding on small roots and the bark of larger roots, while prairie and meadow voles chew on lower trunk bark. In addition to the direct feeding damage, vole tunneling also destroys the root ball. In containerized plants voles cause feeding damage and remove substrate from containers leaving roots exposed.

Single-dose rodenticides require only one feeding to be lethal. Multiple-dose (anticoagulant) rodenticides are slow acting because voles poisoned with anticoagulants die from internal bleeding. The most effective and potent anticoagulant rodenticides contain cholecalciferol, brodifacoum, bromadiolone, chlorophacinone, and coumafuryl.

Place the bait in runways or next to burrows so voles will find it during their daily travels. One method of keeping bait in a palatable state is to establish bait stations. You can purchase commercial bait stations or make your own from 2- to 3-inch diameter plastic pipe.

Source: U.K. Pub. FOR-43, Managing Rabbit and Vole Problems in Kentucky Orchards;University of Maryland, Pub. FS654, Reducing Vole Damage to Plants in Landscapes, Orchards, and Nurseries.

Loosen Tags
Now is a great time to check trees for tags and stake ties that have become too tight as trees have increased in caliper over the season. Several instances of this have been seen in the last few weeks. Plastic and wire tags that are too tight can cause girdling, restricting water and sugar transport up and down the tree. Trees are stunted and can die from girdling. Girdling also causes a weak spot in the trunk which may fail as the canopy becomes larger. Evidence of girdling can reduce the salability of the tree.

Photo by Dr. Win Dunwell.

Comparison of 5 Controlled Release Fertilizers
A study done by University of Georgia researchers compared 5 fertilizers under south Georgia conditions. The fertilizers tested were Gracote 18-5-14, Multicote 17-5-11, Nutricote Total 17-6-8, Osmocote Plus Southern Formula 15-9-12, and Polyon NPK+ 17-5-11. They were tested on Acer x freemanii Autumn Blaze Maple in #5 containers. None of the fertilizers produced a plant with significantly greater height or stem diameter but the plants fertilized with Gracote were lighter green.

Gracote provided ample nutrients for less than 150 days while all other fertilizers provided sufficient nutrients for 180 days, based on EC readings.

Source: Georgia Green Industry Association Journal, April 2002.