Pest Alert

W  Aphids are still showing up everywhere and are found on almost any plant, though ash, elms and walnuts generate most of the calls.  Generally the concern is about a “weeping tree” or one that is dipping sap.  The culprit is not tree sap but honeydew a byproduct of the aphids feeding on the tree leaves.  The honeydew is sticky and often dark colored due to a fungus – called sooty mold – that lives on the honeydew.  The feeding damage from the aphid is usually minimal.  We have received reports of tree companies leaving flyers at homes stating that their trees have aphids and need to be sprayed.  In one case the notice said the birch had aphids that needed treatment but the tree was an aspen, not a birch, and there were no aphids!  While treatments are justified in some instances – excessive honeydew on the patio, perhaps, or a young tree that is heavily infested – generally no control is recommended.

F APPLE MAGGOTS.  The “railroad worm”, as it is called, is the larvae of a small insect that resemble a house-fly but has dark markings on the wings.  The adult emerges from the soil and goes off in search of apples.  The adult lays an egg just under the skin of the apple.  The egg soon hatches into the maggot that feeds inside the apple.  Infested apples will typically have a small black speck on the skin of the apple.  The apple may also be “dimpled” where the egg has been laid.  Small brown streaks will be seen in the flesh of the apple where the maggot has fed.  Infested fruit, while unattractive, is still edible but has a much shorter storage life.  Sticky red ball traps may be used to monitor for the emergence of the adults.  Begin treatment when five adults have been captured on a sticky ball. Apply protective sprays of malathion, diazinon, Imidan or use a combination orchard spray to reduce infestations.  Some people have reported good results by simply using 6 to 8 sticky traps in a few trees in a yard to reduce damage to tolerable levels without using insecticides.

L  DAMAGE FROM WHITE GRUB INFESTATIONS in lawns begins to appear this time of year. Symptoms include a general browning of the turf similar to severe drought stress.  This is due to the severing and consumption of turfgrass roots by the final larval instar stage of certain Scarab beetles, such as May/June beetles, Masked Chafers, and Black Turfgrass Ataenius.  With little or no roots, the turf cannot take up water and is no longer anchored in the soil.  Large patches of turf can be easily lifted from the lawn. Oftentimes, damage from foraging animals such as skunks, raccoons, moles, and birds is more severe than the actual grub damage.  Rolling back the sod should reveal a cream-colored, C-shaped grub with a tan to brown head and three sets of prolegs.  If populations are less than 8 to 10 per square foot for Masked Chafers or 3 to 5 per square foot for May/June Beetles, persistent watering may allow turf survival without the use of insecticides.  If chemical treatment is warranted, Dursban or Diazinon can be applied now.  Be sure to follow insecticide applications with 1” of water in order to move the product into the soil where the grubs are feeding.  Since grub populations in the lawn are usually concentrated in certain areas, scouting for these areas and spot treating can reduce insecticide amounts.  If populations are present this year, consider using one of two new products, Merit or Mach 2, next year.  These products have low mammalian toxicity, are more environmentally friendly, and have season-long residual activity when applied in Spring.  Don’t apply Merit or Mach 2 this late in the season since their mode of action affects growth regulation between larval instar stages, and won’t be effective.

F,W GRAPE LEAFHOPPERS have been busy feeding on grapes and related plants like Boston Ivy and Virginia Creeper.  These tiny sucking insects often feed in great numbers giving the leaves a grayish appearance due to the numerous stipple marks on the leaves.  The insects are rather difficult to see at first but will often fly around when the plant is disturbed.  They feed on the underside of the leaf and may leave dark brown to black spots of fecal material on the leaves.  Treatment with malathion should be effective.

F  RASPBERRY CANE BORERS may be attacking raspberry plants in the garden.  This adult borer chews two rings around the stem, near the top and lays her egg in the stem.  Later, the top of the stem dies while the larvae begins feeding and tunneling in the stem.  Best control is to prune out any canes that show this feeding activity.

 OTHER NOTES

W  Basswood leaves are turning brown and falling.  Actually it is not the leaves, but the leafy bract that subtends the nutlets the trees produce.  During mid- to late summer these are dropped and the ground beneath the tree is littered with what appears to be small, elongated brown leaves.  This is just a normal process for basswoods and lindens.  These trees may also have some of their leaves turn brown at this time of year.  While not attractive, this is also a common occurrence during late summer.

W  Why is the ground covered with the tips of pine branches?  This is a question we sometimes get during late summer.  Squirrels often nip the tips of branches after the new growth has hardened.  If you look closely at the fallen branch tips you’ll find that the tips have been severed cleanly and only along the current year’s growth.  Why squirrels do this is anyone’s guess but they can be seen feeding on the sap that drips from the wounds.  The amount of feeding damage is usually too small to be of any concern.  No control is recommended.

L  LAWN RENOVATION time is here.  Aug. 15 to Sept. 15 is considered the best time of year to start a new lawn or renovate an old one by either seeding or sodding.  The first step is to kill existing vegetation.  One of the easiest ways to do this is to use a non-selective herbicide like glyphosate, sold as Round-Up, Kleen-Up, and a number of other trade names. Follow label instructions for treatment recommendations.  The old grass and weeds should be actively growing and have several inches of growth for best results.  Do not mow for a couple weeks to encourage more growth and water the area a few days in advance to promote growth during dry weather.    If a soil test has not been done in the area for several years, now is also a great time to gain some important information that could allow you to correct a problem that could cause reduced grass establishment or stand in the future. Once the old vegetation has been killed, you are ready to begin reworking the soil and adding any amendments that may have been recommended from the soil analysis.  Be sure to select an appropriate lawn grass or mixture for your yard.  Make sure to get good seed to soil contact when seeding.  Be prepared to supply supplemental irrigation during establishment, keeping the seedbed moist for at least 3 weeks.