October 15, 2004.cdr
October 15,
INSECTS
2004
Issue 25
Derby Walker Extension Agent
What's Hot!
BANDED WOOLLY CATERPILARS are starting to wander from the weeds they feed on in the fall. They over winter as caterpillars and will pupate in the spring after feeding for a few days. Their wandering habits upset some people, but they do little harm. They can not be used to predict the weather.
The egg cases of the two common species of praying mantis will soon be showing up attached to branches and even the sides of structures. These foam-like structures contain hundreds of eggs. Leave them attached to hatch next spring. Egg cases on the ground will be destroyed by ants.
JUNE BEETLE LARVAE have been feeding on turf leaving behind a hole with a small mound of soil. Fescue lawns seem to tolerate the root feeding better than other species. The weather change has caused grubs to leave the soil. Homeowners are usually more troubled by the holes and the large grub crawling around (it crawls on its back than the turf injury). The grubs often end up on the patio, driveway, in the garage, or in other structures. They don't survive indoors but people don't like to see these two-inch grubs. The size of the grub will make control difficult. These grubs spend the winter underground and emerge from the soil next summer. SPIDERS are every where in the fall. They seem to come from nowhere. Their numbers have been building all summer as their food supply increases. These valuable predators help hold down insect populations. For the most part we are only concerned with the black widow and brown recluse spiders, both of which are more common in Southern Delaware.
DISEASES Bob Mulrooney Extension Plant Pathologist BIRCH LEAFSPOT. In late summer and early fall I see Septoria leafspot on birch. Recently I saw this leafspot infecting river birch, Betula nigra, and White Barked Himalayan Birch, Betula jackmontii. It will not affect plant health at this time of year but does cause some premature defoliation. Rake and remove leaves or compost. ROSES. Cercospora leafspot, is present on climbers and some shrub roses. Cercospora produces small spots with red borders and gray centers. It is rarely seen on hybrid tea roses here.
Lady bug beetles will survive the winter in protected places, for example, under loose bark, under boards or logs, in clumps of grass or piles of leaves next to a tree trunk or buildings and some will hibernate in wall voids. Providing over wintering sites helps them survive and that may help reduce your pest insect problems next year. Elongate hemlock scale is present now on hemlocks and some firs as both adults and nymphs (both are overwintering stages). Use dormant oils to reduce the overwintering populations of this damaging pest. Southern red mite eggs and nymphs are present on many broadleaved evergreens. Use a dormant oil spray, being sure to coat the undersides of leaves to control the overwintering eggs and nymphs still feeding this fall.
For more ion informat on pests & practices covered in this newsletter, call your County Extension Office Helpful numbers to know:
MULCH FUNGI. The wet weather last week has produced a new crop of mushrooms in mulch. Several samples of stinkhorns were submitted this week. The dog stinkhorn is very common (Continued)
UNIVERSITY OF DELAWARE
Garden Line 831-8862 (for home gardeners only) New Castle County Extension 831-2506 Kent County Extension 730-4000 Sussex County Extension 856-7303
COOPERATIVE EXTENSION
Cooperative Extension Education in Agriculture and Home Economics, University of Delaware, Delaware State University and the United States Department of Agriculture cooperating. Janice A. Seitz, Director. Distributed in furtherance of Acts of Congress of March 8 and June 30, 1914. It is the policy of the Delaware Cooperative Extension System that no person shall be subjected to discrimination on the grounds of race, color, sex, disability, age, or national origin.
Diseases (Continued)
and is long and pointed with no cap. The upper part of the stalk is covered with an orange-to brown spore slime that smells terrible. These are harmless and can be broken up with a rake. TAR SPOT ON RED MAPLE is fairly common this time year. The black tar-like crusty spots caused by the fungus Rhytisma are very evident now especially when you begin to rake up the leaves. This is a late season leafspot that does not affect the health of the trees.
Editor: Susan Barton Extension Horticulturist
Cooperative Extension Townsend Hall Newark, Delaware 19717
2004 r 12, Octobe AS OF
GROWI DAYS DEGREE NG
A) =N '03 e 70 ( ous ) =34 y enh e c i Gre Count Off A) her e N n o = i Fisc Castl wn ('03 tens w (Ne geto y Ex 3 8 7 8 eor u nt r, G = NA) ty) = t Co 3 ente Ken t Coun c. C 059 ('0 (Ken Edu 4 h & nty) = u earc Res sex Co (Sus
INSECTS
2004
Issue 25
Derby Walker Extension Agent
What's Hot!
BANDED WOOLLY CATERPILARS are starting to wander from the weeds they feed on in the fall. They over winter as caterpillars and will pupate in the spring after feeding for a few days. Their wandering habits upset some people, but they do little harm. They can not be used to predict the weather.
The egg cases of the two common species of praying mantis will soon be showing up attached to branches and even the sides of structures. These foam-like structures contain hundreds of eggs. Leave them attached to hatch next spring. Egg cases on the ground will be destroyed by ants.
JUNE BEETLE LARVAE have been feeding on turf leaving behind a hole with a small mound of soil. Fescue lawns seem to tolerate the root feeding better than other species. The weather change has caused grubs to leave the soil. Homeowners are usually more troubled by the holes and the large grub crawling around (it crawls on its back than the turf injury). The grubs often end up on the patio, driveway, in the garage, or in other structures. They don't survive indoors but people don't like to see these two-inch grubs. The size of the grub will make control difficult. These grubs spend the winter underground and emerge from the soil next summer. SPIDERS are every where in the fall. They seem to come from nowhere. Their numbers have been building all summer as their food supply increases. These valuable predators help hold down insect populations. For the most part we are only concerned with the black widow and brown recluse spiders, both of which are more common in Southern Delaware.
DISEASES Bob Mulrooney Extension Plant Pathologist BIRCH LEAFSPOT. In late summer and early fall I see Septoria leafspot on birch. Recently I saw this leafspot infecting river birch, Betula nigra, and White Barked Himalayan Birch, Betula jackmontii. It will not affect plant health at this time of year but does cause some premature defoliation. Rake and remove leaves or compost. ROSES. Cercospora leafspot, is present on climbers and some shrub roses. Cercospora produces small spots with red borders and gray centers. It is rarely seen on hybrid tea roses here.
Lady bug beetles will survive the winter in protected places, for example, under loose bark, under boards or logs, in clumps of grass or piles of leaves next to a tree trunk or buildings and some will hibernate in wall voids. Providing over wintering sites helps them survive and that may help reduce your pest insect problems next year. Elongate hemlock scale is present now on hemlocks and some firs as both adults and nymphs (both are overwintering stages). Use dormant oils to reduce the overwintering populations of this damaging pest. Southern red mite eggs and nymphs are present on many broadleaved evergreens. Use a dormant oil spray, being sure to coat the undersides of leaves to control the overwintering eggs and nymphs still feeding this fall.
For more ion informat on pests & practices covered in this newsletter, call your County Extension Office Helpful numbers to know:
MULCH FUNGI. The wet weather last week has produced a new crop of mushrooms in mulch. Several samples of stinkhorns were submitted this week. The dog stinkhorn is very common (Continued)
UNIVERSITY OF DELAWARE
Garden Line 831-8862 (for home gardeners only) New Castle County Extension 831-2506 Kent County Extension 730-4000 Sussex County Extension 856-7303
COOPERATIVE EXTENSION
Cooperative Extension Education in Agriculture and Home Economics, University of Delaware, Delaware State University and the United States Department of Agriculture cooperating. Janice A. Seitz, Director. Distributed in furtherance of Acts of Congress of March 8 and June 30, 1914. It is the policy of the Delaware Cooperative Extension System that no person shall be subjected to discrimination on the grounds of race, color, sex, disability, age, or national origin.
Diseases (Continued)
and is long and pointed with no cap. The upper part of the stalk is covered with an orange-to brown spore slime that smells terrible. These are harmless and can be broken up with a rake. TAR SPOT ON RED MAPLE is fairly common this time year. The black tar-like crusty spots caused by the fungus Rhytisma are very evident now especially when you begin to rake up the leaves. This is a late season leafspot that does not affect the health of the trees.
Editor: Susan Barton Extension Horticulturist
Cooperative Extension Townsend Hall Newark, Delaware 19717
2004 r 12, Octobe AS OF
GROWI DAYS DEGREE NG
A) =N '03 e 70 ( ous ) =34 y enh e c i Gre Count Off A) her e N n o = i Fisc Castl wn ('03 tens w (Ne geto y Ex 3 8 7 8 eor u nt r, G = NA) ty) = t Co 3 ente Ken t Coun c. C 059 ('0 (Ken Edu 4 h & nty) = u earc Res sex Co (Sus
