September 17 2010
INSECTS
September 17, 2010
Issue 23
Brian Kunkel Ornamental IPM Specialist BANDED WING WHITEFLIES are actively feeding at this time of year and were recently found on Hibiscus. Other ornamental host plants may include Euphorbia, Geranium, Petunia among others and possible populations may be found on nearby weeds such as Ambrosia, Bidens, and Sida. Adults hold their wings roof-like over their bodies and the wings have a gray zig-zag pattern. Nymphs are translucent white with yellow spots and eventually form a wax fringe with translucent setae. Leaves become chlorotic as sap is removed and sooty mold growing on the honeydew is often found with infestations. Lady beetles, parasitoids, and lacewings all feed on whiteflies. Yellow sticky cards help monitor for when populations arrive or begin to increase at locations. Products available for control include: abamectin, azadirachtin, Beauvaria bassiana, horticultural oil, insecticidal soap, pyriproxyfen, spiromesifen, imidacloprid, acetamiprid, dinotefuran, pyrethroids, and acephate. BOXELDER BUGS are black and red or orange as adults. Nymphs are bright red in color and may be found with adults in mixed age populations during the summer. This insect feeds on low lying vegetation and seeds of box elders, maples and ash trees but rarely causes significant injury to these plants. They become a nuisance during the fall as they migrate to houses and buildings heated by sunlight especially on the southern or western exposures. Box elder bugs can stain surfaces when they are killed or with their excrement. Control options include winterizing the structure by caulking and screening cracks, crevices, holes, windows, vents and doors as needed. Exclusion is the best method to keep this nuisance pest to a minimum. Pesticide applications to the outside of homes or structures is rarely recommended because pesticides generally will break down within seven to ten days; however if the label permits application to the exterior of homes products such as pyrethroids may provide short term relief from heavy pressure from nuisance insects.
What's Hot! University of Maryland has trapped banded ash clearwing borer males in pheromone traps, so now is a good time to protect ash trees with barks sprays of Onyx or Astro. Locust borers were spotted in New Castle County. Brown Marmorated Stink Bugs are beginning their fall migration to homes and structures. Editor’s Note: You may have noticed the lack of Ornamentals Hotline last week. We have gotten to that part of the season where we publish Hotline every other week. Since there is less going on in the landscape now (especially with this dry weather), we can use the next 3 issues to cover all the fall insects, diseases and cultural notes if we publish every other week. Look for Issue 24 on October 1.
Fornfomromrae tion i
on pests & practices covered in this newsletter, call your County Extension Office
DISEASES Bob Mulrooney Extension Plant Pathologist
Helpful numbers to know:
LEAFSPOT DISEASES. At this time of the year with all the plant stress from the high temperatures and lack of rainfall, several trees and shrubs are showing symptoms of late season leaf spot diseases. These are strictly cosmetic now and should not affect (Continued)
UNIVERSITY OF DELAWARE
Garden Line (for home gardeners only) New Castle County Extension Kent County Extension Sussex County Extension
831-8862 831-2506 730-4000 856-7303
View pictures at http://ornamental diagnostics.blogspot.com/
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) plant heath by themselves. Several recently seen are Phyllotsticta leafspot on London plane tree and sycamore. It produces a round brown spot on the leaves which can coalesce and affect large areas of the infected leaves. Septoria leafspot on flowering dogwood and red twig dogwood (C. sericia 'Silver and Gold') is also present in some locations. These small angular spots often with red-brown margins can be found especially where there has been some overhead irrigation. It often resembles anthracnose but at the wrong time of the year. On annuals I have seen Alternaria leafspot on fragrant heliotrope which produces an indistinct dark brown to black blotch on the leaves. I also spotted a new leafspot for me on Oxeye or Heliopsis helianthoides var. scabra 'Sommersonne'. The fungus Phyllosticta was the cause of this leafspot. FOLIAR NEMATODES were diagnosed this past week on Brunnera macrophylla 'Jack Frost', herbaceous peony, Hosta, plumbago, Black Widow cranesbill, and Japanese anemone. Look for the angular brown to yellow spots that are limited by the vein pattern of the leaf. Remove and destroy infected leaves if practical. Clean up infected foliage at the end of the season. There are no chemical controls in the landscape at the present time. Editor: Susan Barton Extension Horticulturist
Cooperative Extension Townsend Hall Newark, Delaware 19717
, 2010 ber 14 Septem AS OF
DEGREE
G GROWINDAYS
55) = 28 (’ 0 9 43 1 = 3 lege Col y, PA) 2 5) ore = 30 nt '09 rthm Cou e 33 ( Swa aware ous ) = 35 l wn y (D e enh geto 3) Gre Count eor her e r, G 9 = 31 7 Fisc Castl ente 0 w c. C 622 (' (Ne 3 Edu h & nty) = u earc Res sex Co ( Su s
September 17, 2010
Issue 23
Brian Kunkel Ornamental IPM Specialist BANDED WING WHITEFLIES are actively feeding at this time of year and were recently found on Hibiscus. Other ornamental host plants may include Euphorbia, Geranium, Petunia among others and possible populations may be found on nearby weeds such as Ambrosia, Bidens, and Sida. Adults hold their wings roof-like over their bodies and the wings have a gray zig-zag pattern. Nymphs are translucent white with yellow spots and eventually form a wax fringe with translucent setae. Leaves become chlorotic as sap is removed and sooty mold growing on the honeydew is often found with infestations. Lady beetles, parasitoids, and lacewings all feed on whiteflies. Yellow sticky cards help monitor for when populations arrive or begin to increase at locations. Products available for control include: abamectin, azadirachtin, Beauvaria bassiana, horticultural oil, insecticidal soap, pyriproxyfen, spiromesifen, imidacloprid, acetamiprid, dinotefuran, pyrethroids, and acephate. BOXELDER BUGS are black and red or orange as adults. Nymphs are bright red in color and may be found with adults in mixed age populations during the summer. This insect feeds on low lying vegetation and seeds of box elders, maples and ash trees but rarely causes significant injury to these plants. They become a nuisance during the fall as they migrate to houses and buildings heated by sunlight especially on the southern or western exposures. Box elder bugs can stain surfaces when they are killed or with their excrement. Control options include winterizing the structure by caulking and screening cracks, crevices, holes, windows, vents and doors as needed. Exclusion is the best method to keep this nuisance pest to a minimum. Pesticide applications to the outside of homes or structures is rarely recommended because pesticides generally will break down within seven to ten days; however if the label permits application to the exterior of homes products such as pyrethroids may provide short term relief from heavy pressure from nuisance insects.
What's Hot! University of Maryland has trapped banded ash clearwing borer males in pheromone traps, so now is a good time to protect ash trees with barks sprays of Onyx or Astro. Locust borers were spotted in New Castle County. Brown Marmorated Stink Bugs are beginning their fall migration to homes and structures. Editor’s Note: You may have noticed the lack of Ornamentals Hotline last week. We have gotten to that part of the season where we publish Hotline every other week. Since there is less going on in the landscape now (especially with this dry weather), we can use the next 3 issues to cover all the fall insects, diseases and cultural notes if we publish every other week. Look for Issue 24 on October 1.
Fornfomromrae tion i
on pests & practices covered in this newsletter, call your County Extension Office
DISEASES Bob Mulrooney Extension Plant Pathologist
Helpful numbers to know:
LEAFSPOT DISEASES. At this time of the year with all the plant stress from the high temperatures and lack of rainfall, several trees and shrubs are showing symptoms of late season leaf spot diseases. These are strictly cosmetic now and should not affect (Continued)
UNIVERSITY OF DELAWARE
Garden Line (for home gardeners only) New Castle County Extension Kent County Extension Sussex County Extension
831-8862 831-2506 730-4000 856-7303
View pictures at http://ornamental diagnostics.blogspot.com/
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) plant heath by themselves. Several recently seen are Phyllotsticta leafspot on London plane tree and sycamore. It produces a round brown spot on the leaves which can coalesce and affect large areas of the infected leaves. Septoria leafspot on flowering dogwood and red twig dogwood (C. sericia 'Silver and Gold') is also present in some locations. These small angular spots often with red-brown margins can be found especially where there has been some overhead irrigation. It often resembles anthracnose but at the wrong time of the year. On annuals I have seen Alternaria leafspot on fragrant heliotrope which produces an indistinct dark brown to black blotch on the leaves. I also spotted a new leafspot for me on Oxeye or Heliopsis helianthoides var. scabra 'Sommersonne'. The fungus Phyllosticta was the cause of this leafspot. FOLIAR NEMATODES were diagnosed this past week on Brunnera macrophylla 'Jack Frost', herbaceous peony, Hosta, plumbago, Black Widow cranesbill, and Japanese anemone. Look for the angular brown to yellow spots that are limited by the vein pattern of the leaf. Remove and destroy infected leaves if practical. Clean up infected foliage at the end of the season. There are no chemical controls in the landscape at the present time. Editor: Susan Barton Extension Horticulturist
Cooperative Extension Townsend Hall Newark, Delaware 19717
, 2010 ber 14 Septem AS OF
DEGREE
G GROWINDAYS
55) = 28 (’ 0 9 43 1 = 3 lege Col y, PA) 2 5) ore = 30 nt '09 rthm Cou e 33 ( Swa aware ous ) = 35 l wn y (D e enh geto 3) Gre Count eor her e r, G 9 = 31 7 Fisc Castl ente 0 w c. C 622 (' (Ne 3 Edu h & nty) = u earc Res sex Co ( Su s
