It seems that our unseasonably warm spring has resulted in more than just an early awakening of our spring blooming favorites like daffodils, magnolias, and forsythias.  Not surprisingly, some of the pests are emerging early this year too.  Yesterday we had the first reported sighting of pine sawfly in the area.  Pine sawfly normally emerges in May & June and can be extremely devastating to pine trees.  Take a minute to review our previous blog post on European Pine Sawfly then head out and start scouting your landscape!

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By Carolyn Johnson

Summer is finally in full swing.  It sure feels like it with all this heat, doesn’t it?  We are now noticing in the garden, the effects of our cool and rainy spring.  Some things to watch for right now in your garden include magnolia scale, Japanese beetles, and cutworm on creeping jenny.

"Wooly" covering of the magnolia scale

Magnolia Scale:  We have seen evidence of scale on magnolias recently.  The scale is shiny and smooth, and often covered with a white, waxy coating.  Branches can become heavily infested which results in weakened or dead wood.  Scale creates a substance called honeydew which is excreted on the plant’s foliage and branches.  Sooty mold, a dark fungus, then develops on the honeydew on the leaves, thus detracting from the ornamental value of the tree.  You can rid the plant of scale by scratching them off (though you would have to remain diligent about this practice), applying horticultural oils in late August, or systemically spraying in late August or early September.

Japanese Beetles: We have begun to spot these insects on ornamental

plants in the past week.  The beetles are shiny, metallic green insects with tufts of white under their wing covers.  Most beetles tend to congregate and can do large amounts of damage by chewing on leaves and flowers of your prized roses.  Don’t think they are limited to roses for feeding, however.  Their taste palette includes more than 300 species of plants ranging from trees to shrubs to non-woody plants, including annuals.  The most effective method of controlling Japanese beetles is to hand pick them off your plants and drop them into a container with soapy water.  There are some contact sprays out there, like insecticidal soap, but if the beetle isn’t hit directly with the spray then it will not be controlled.  If you notice a large infestation of Japanese beetles, you may want to check your turf.  The beetles start as grubs in your turf and can cause the turf to die.

Cutworm and feeding damage on creeping jenny

Cutworm: We have been noticing a lot of cutworm damage to the creeping jenny ground cover as well.  It’s seems to be worse this year than in the past and possibly due to the wet spring we’ve experienced.  The leaves are practically chewed to nothing leaving the stems of the plant looking very sad, indeed!  We spread a natural product called Diatomaceaous Earth that you can find at your local garden center.  The product has an abrasive feel that when the exoskeletons of pests, such as cutworm and slugs, cross over the product it causes the insects to dehydrate and die.

We hope this gives you a few things to be watchful for in your gardens.  If you have any questions, please feel free to contact us.

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By Ann Davenport

Hostas are a mainstay in our landscapes.  They are a tough, reliable, “hassle-free” plant with what seems like thousands of varieties from which to choose.  While hostas are considered to be relatively disease free, they are susceptible to a virus referred to as Hosta Virux X (HVX).

HVX was first identified in 1996 by Dr. Ben Lockhart at the University of Minnesota.  It has become a common virus in hosta and is a concern to nurseries, garden centers, and home owners alike.  Hosta Virus X is not transmitted through insects, nematodes, seed, or pollen transfer.  Rather, the virus is transmitted mechanically through wounds resulting in sap to sap contact during dividing, transplanting, trimming, etc…  Once a plant has HVX there is no cure and the plant must be destroyed.

HVX reduces plant vigor and most symptoms are displayed in a deterioration of leaf quality.  Symptoms can include line patterns (often along veins), mosaic patterns, blotches, twisting or puckering of leaves, and necrotic (dead) spots.  Symptoms vary among cultivars and may take years to develop.

Since there is no cure for HVX the best management strategy is to prevent the spread.  Plants with the virus should be removed from the garden and destroyed.  Do not compost infected plants as the virus can live in infected soil for up to two years.  It is good practice to sterilize your tools regularly and it is especially recommended to do so between plants when cutting or dividing.  Sterilization can be done by using a solution of Dawn dish soap, 70% alcohol solution, or a 10% bleach solution.  In all cases it is not enough to simply dip the tool in the solution.  Tools must be scrubbed clean of all dirt and debris.

Additional information can be found online by visiting American Hosta Society and University of Minnesota Extension Yard and Garden News.

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By Ann Davenport

May and June is the time to get out into your garden and take a look at your pine trees.  Do they look like they are losing their needles?  Take a closer look.  Do you see little worms on the old needles?  If so, you are likely looking at European Pine Sawfly.  European Pine Sawfly are part of the wasp family.  It is the larvae stage that eats your pine needles.  The larvae are about an inch long with a black head and a gray-green body.

They feed in groups on the previous year’s needles.  Mugo, Scotch, Jack, and Red pine are favored by European Sawfly.  White and Austrian pine are less susceptible.

Early detection is the best method of control for the European Pine Sawfly.  Begin inspecting your evergreens in early May for signs of feeding.  If caught early, they can easily be removed by hand.  You can blast them off with a hose or spray with an insecticidal soap (you can purchase it or make your own with liquid dish soap).  You may need to spray a couple times a week during the feeding season.  As larvae mature, insecticidal soap becomes less effective and you may need to step up to an insecticide containing pyrethrin.  This can be found at a hardware store or garden center.

To make your pines happier and healthier and less attractive to sawfly, water them regularly throughout the summer and up to the first frost.  One to two defoliations won’t kill an otherwise healthy pine.  The new growth isn’t affected and barring no other disease or insect factors, the plant should recover.

For additional information about European Pine Sawfly as well as other Sawfly species found in Minnesota take a look at this University of Minnesota Extension publication.

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By Ann Davenport

I love a good Pagoda Dogwood (Cornus alternifolia).  Its defined shape adds an element of architecture to the garden.  White flowers and bluish berries on red stems provide multiple season interest in our outdoor world.  Sadly, this great shrub/small tree is susceptible to a disease know as golden canker.  Upon first look, infected branches are a not entirely unpleasant orange-yellow color in contrast to the dark reddish-purple healthy bark.  A closer look at the yellow branch will reveal hundreds of tiny, blister-like orange spots.  A distinct line marks the area between healthy and diseased tissue.  Any branch that has turned completely yellow is dead and will not leaf out.

Golden Canker is caused by the fungus Cryptodiaporthe corni.  Very little is known about this fungus other than that it only affects Pagoda Dogwoods, especially those which are heat and drought stressed.

It advances within the plant while the plant is dormant.  Any branch that is completely encircled by the fungus will die and if the fungus reaches the main stem of the plant, the entire canopy may die.

If you have a Pagoda Dogwood in your landscape, there are several things that can be done to either reduce the risk of acquiring golden canker or help control the disease in already infected plants.  It is important to visually inspect the dogwood in the spring before new growth begins.  Any infected branches should be removed several inches below where the infected bark meets the healthy bark.  The fungus travels in advance of that “dead” line so cutting farther back into healthy tissue increases the chance of removing all of the infected tissue.

It is also important to sterilize your cutting tool between cuts so as not to transfer fungal spores to uninfected tissue.  Any infected branches should be disposed of (not composted) and removed from the area.

Providing optimum growing conditions for the plant can reduce the chances of it becoming infected.  Pagoda Dogwood is native to our region and is typically found as a small understory tree, preferring shaded to partially shaded areas.  Providing a similar environment in the home landscape will help reduce stress to the plant.  Also, mulching around the base of the plant will help keep roots cool and retain needed moisture.  During dry periods supplemental water should be provided.

With a little bit of care and a few extra steps, pagoda dogwoods can thrive in our landscapes.  They add a unique quality that is difficult to replicate and well worth that little bit of extra time.

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The Japanese Beetle can be one of the most destructive garden pests, especially on roses, raspberries and linden trees. Late June to the end of July are the prime foliage eating times for the Japanese Beetle adults and one of our clients has spotted them in her garden already.The Ohio State Extension Fact Sheet lists several options to control or minimize Japanese Beetle damage… these are the two that make the most sense:Option 1: Cultural Control – Hand Picking The first Japanese Beetles that arrive in your garden are often “scouts.” They chemically signal other Japanese Beetles to join them at the feast. By noticing when the first adults arrive on a property, you can pick off and destroy these scouts that attract additional pests. The adults are less active in the early morning or late evening. They can be destroyed by dropping into a container of soapy water.Option 2: InsecticideThe adults can be controlled by spraying susceptible plants with insecticides. Over-the-counter pesticides available for this include: acephate (Orthene), carbaryl (Sevin), and several pyrethroids – bifenthrin, cyfluthrin, deltamethrin, lambda-cyhalothrin, permethrin, and others. Applications of imidacloprid (=Bayer Advanced Tree & Shrub Concentrate) generally need to be made 20 days before anticipated Japanese beetle adult activity. During the heavy adult activity periods, sprays may be needed every 5 to 10 days.A couple of important notes – there is no “Japanese Beetle” specific insecticide, so the insecticides will kill other insects in the process, some of which may be beneficial in your garden. Also, there is a Japanese Beetle look alike called the False Japanese Beetle. It is more greenish black in color and will not have the distinctive 5 hairy stripes on the side that the Japanese Beetle has.

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This weekend we saw the first saw fly larvae on a pine tree. Double-check your pines for this pesky pest – they are tiny worm-like larvae of the saw fly and their voracious appetites can defoliate even large trees. You can spray the tiny monsters off with a garden hose or, on larger trees, call your friendly arborist for control measures.

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