Needle Cast In Spruce

Do your spruce trees look like they have short pants? A little thin? You may have Needle Cast Disease and not know it!

Evergreens typically retain their needles for up to 3 years. If they are stressed or suffering from drought or disease they can lose them in one season. The investment the trees make in the needles costs them valuable resources and when they lose them prematurely they begin a downward spiral that may lead to death.

Needle Cast Diseases are fungi and in spruce trees they are generally two types,

Rhizosphaera needle cast or Stigmina needle cast. These are caused by Rhizosphaera kalkhoffii, and  Stigmina lautii respectively.These can be diagnosed by looking at the fruiting bodies on infected needles with a microscope or strong hand lens. Rhizosphaera fruiting bodies are rows of small smooth edged black dots coming out of the stomata, tiny breathing holes, on the browning needles. Stigmina fruiting bodies are black, in rows and are not as round or clearly defined as Rhizosphaera.

Infected needles will turn bronze and be dropped prematurely. This needle drop causes the tree to decline and look sparse. Eventually the tree may die. Wet humid conditions and lack of air flow all increase the chance of this disease spreading and damaging your trees.

Chemical fungicides are effective in controlling this disease. They must be applied according to label directions and typically two or three applications are required. When the needles are half elongated and when they are fully elongated is the recommended timing. These treatments will need to be applied on a yearly basis for several years until the plants recover. In the case of Stigmina this may be needed yearly.

Avoid watering on the foliage, keep groups of trees spaced well to increase air flow. Prune out dead branches and remove badly affected trees to limit the spread of the disease.

If you have questions Certified Arborists are industry recognized experts in plant insect and diseases control. Contact your I.S.A. Certified Arborist to see if you think you have this damaging plant disease.

Spots On Your Apples

 

 

 

 

If you would like to not have spots on your apples and leave the birds and the bees this article may be just what you’re looking for. Apple Maggot, Rhagoletis pommonella, is a small fly that infests a variety of hosts including crab apple, apples, plum, hawthorn, and occasionally apricots. It has a wide range from North Eastern United States through to Southern Manitoba, Canada

The spots on your apples are created when the female of the species punctures the skin of the fruit laying her eggs. The eggs then hatch and burrow though the apples causing the characteristic traces or brown discolored tunnels in the flesh of the fruit. The plant often responds by dropping infected fruit. Once the fruit is dropped the larvae emerge and pupate in the soil under the host tree. Some fruit remains on the host until fall and larvae develop at a slower pace in these fruits. This leads to a long period of emergence for adults in t the following spring.

Adults emerge the following spring just after the apples have finished blooming and continue to emerge for the next two months. The insects are small flies, slightly smaller than a house fly with black bodies and distinctive black bands on their clear wings. They emerge sexually immature and take a week to 10 days to fully develop. While maturing they feed on honeydew secreted by aphids. Once mature they congregate and mate on fruit.

The female lays as many as 300 eggs in her 30 day life span.

Control of this pest is difficult due to the long period of adult emergence. Chemical controls can be effective if applied at the very end of the flowering period and every 10 days thereafter until the adults are no longer emerging. Time applications to begin after flowers start to loose petals and you will have minimal impact on pollinators such as bees. Horticultural oils can reduce the population of aphids and limit food sources for immature adults. Bright red plastic sticky apples and yellow paper sticky traps can be used to scout for the emergence of adults. Culturally, prompt removal of all dropped apples throughout the season helps to break the life cycle. Dropped apples should be disposed of sanitarily off site. Removing alternate hosts in wild adjacent areas will also help to reduce populations. 

If you have questions about apple maggot contact your I.S.A. Certified Arborist to see if you have this damaging plant pest.

I.S.A Certified Arborists are industry recognized experts in plant insect and diseases control.