re Fo mor t informaion
INSECTS
July 10,
2009
Issue 15
WEEDS
Brian Kunkel Ornamental IPM Specialist
Stephen Hart Extension Weed Specialist, Rutgers
BLACK VINE WEEVIL adults (87-3644 [1259 peak] GDD50) feed on over 100 plants such as Taxus, hemlocks, euonymus, mountain laurel and rhododendrons. Magnolia x soulangiana in full bloom signals the beginning of adult activity. This flightless weevil feeds during the night and rests at the base of plants during the day. Adults are gray to brownish black. Larvae are c-shaped, legless, and creamy colored with brownish heads.
POSTEMERGENCE CRABGRASS CONTROL. Heavy rains and cool weather this spring means many preemergence herbicide applications will fail. Rain washes the herbicides out of the crabgrass germination zone and cool temperatures prolong crabgrass germination. Maintaining a dense and healthy turfgrass stand is the best defense against crabgrass. However, if summer stresses that thin and weaken the turfgrass stand occur, postemergence herbicides may needed.
Larvae feed in early spring and emerge from pupae in late-May to June. Adults (all female) feed for 21-45 days before egg laying in July when each female oviposits about 200 eggs in the soil or leaf litter around the plant. Adult feeding appears as notches on leaves. Larvae prefer to feed on young roots, but scarce roots and moist soil results in stem feeding that can eventually girdle plants. Larvae feed until soil temperatures force them to dig deeper to overwinter. TWOBANDED JAPANESE WEEVIL adults (1267- 1897 [1555 peak] GDD50) feed on ash, cherry laurel, pyracantha, privet, rose, spirea, forsythia, lilac, barberry, flowering dogwood, broad-leaved evergreens, and others. This flightless weevil is light to dark brown and feeds during the day on new leaves, shoots and inner foliage, but drops to the ground when disturbed. Remove excessive mulch to prevent overly moist soils around susceptible plants. Entomopathogenic nematodes, Heterorhabditis and Steinernema spp., offer variable control of larvae in field plots but have performed better in container soil in greenhouses. Adult chemical control includes acephate, pyrethrins, piperonyl butoxide, and cyfluthrin and imidacloprid. The twobanded Japanese weevil is resistant to sevin and malathion.
DISEASES Bob Mulrooney Extension Plant Pathologist SLIME MOLDS continue to appear in mulched beds. These patches of white, pink or light yellow powdery masses can be found in mulch on stems of plants and other objects. These powdery masses are the reproductive stages of these fungi. The good news is-- they cause no harm to the plants. They can be dispersed with a strong stream from a garden hose or broken up with a rake. Slime molds are often called “dog vomit fungus,” which is fairly descriptive. HOLLYHOCK RUST is now very evident on susceptible cultivars. Numerous orange-red pustules can be seen on the underside of the leaves. The upper surface will be yellowed. If control is needed, spray with Immunox, Funginex, or Daconil for control.
UNIVERSITY OF DELAWARE
Acclaim extra and Drive are most effective when applied to young, actively growing crabgrass with good soil moisture. Herbicide applied under drought and/or heat stress may result in reduced control and increased potential for turfgrass injury. Apply with flat fan nozzles producing a fine spray droplet (avoid flood jets). You can apply these herbicides in combination with residual preemergence herbicides. However, residual herbicides applied late in the season may interfere with late summer/fall overseeding. Acclaim Extra: The rate of Acclaim Extra is dependent on turf species and crabgrass growth stage. Don't exceed 20 oz/A on well established Ky bluegrass (label states up to 28 oz/A) Tall and fine fescue and perennial ryegrass are very tolerant. At 20 oz/A Acclaim Extra is effective on crabgrass up to 2 tillers (in some cases up to 3-4 tillers).
Fornfomromrae tion i
(Continued)
on pests & practices covered in this newsletter, call your County Extension Office Helpful numbers to know: 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.
Weeds (Continued) Tank-mixing or applying Acclaim Extra prior to or following a broadleaf weed herbicide (especially 2,4-D and/or MCPP) may reduce weed control. The formulation contains an adjuvant but depending on application equipment, nonionic surfactant (NIS) may be needed. Drive: Safe on Kentucky bluegrass, perennial ryegrass and tall fescue. Consult the label for use on bentgrasses and fine fescue. Drive can be effective on 2-4 tillered crabgrass and active on large multi-tillered crabgrass when in its reproductive phase (visable seedheads). No goosegrass control. Drive is tank-mix compatible with broadleaf herbicides. Apply with methylated seed oil (MSO). Two formulations are available: Drive 75 DF and a new liquid formulation Drive XLR8 1.5 L (more consistent control in some studies). Combination Products: Q4, Quincept, and Onetime contain Drive in combination with broadleaf herbicides or in the case of Q4 also contain sulfentrazone for yellow nutsedge. Consult labels to determine if a spray adjuvant is recommended. Also determine the use rate of quinclorac (the active ingredient in Drive). Applying quinclorac at less than 0.75 lbs ai/A and/or without a spray adjuvant such as methylated seed oil may reduce the consistency of crabgrass control especially if the growth stage has exceeded one-tiller. Solitare: Contains quinclorac and sulfentrazone (the active in Dismiss) to control/suppress crabgrass and sedges as well as some broadleaf weeds. Looks promising due to potential synergy on crabgrass by using both herbicides together, but only in our 2nd year of testing. Sulfentrazone shows potential to control small (1-4 leaf) goosegrass. Editor: Susan Barton Extension Horticulturist
Cooperative Extension Townsend Hall Newark, Delaware 19717
, 20 09 July 7 AS OF
DEGREE
G GROWINDAYS
13 = 13 lege Col y, PA) 6 8) ore = 14 nt '08 rthm Cou e 83 ( Swa aware ous ) = 13 l wn y (De enh geto Gre Count eor her e r, G = NA) Fisc Castl 8 ente w c. C 495 ('0 (Ne Edu 1 h & nty) = u earc Res sex Co ( Su s
July 10,
2009
Issue 15
WEEDS
Brian Kunkel Ornamental IPM Specialist
Stephen Hart Extension Weed Specialist, Rutgers
BLACK VINE WEEVIL adults (87-3644 [1259 peak] GDD50) feed on over 100 plants such as Taxus, hemlocks, euonymus, mountain laurel and rhododendrons. Magnolia x soulangiana in full bloom signals the beginning of adult activity. This flightless weevil feeds during the night and rests at the base of plants during the day. Adults are gray to brownish black. Larvae are c-shaped, legless, and creamy colored with brownish heads.
POSTEMERGENCE CRABGRASS CONTROL. Heavy rains and cool weather this spring means many preemergence herbicide applications will fail. Rain washes the herbicides out of the crabgrass germination zone and cool temperatures prolong crabgrass germination. Maintaining a dense and healthy turfgrass stand is the best defense against crabgrass. However, if summer stresses that thin and weaken the turfgrass stand occur, postemergence herbicides may needed.
Larvae feed in early spring and emerge from pupae in late-May to June. Adults (all female) feed for 21-45 days before egg laying in July when each female oviposits about 200 eggs in the soil or leaf litter around the plant. Adult feeding appears as notches on leaves. Larvae prefer to feed on young roots, but scarce roots and moist soil results in stem feeding that can eventually girdle plants. Larvae feed until soil temperatures force them to dig deeper to overwinter. TWOBANDED JAPANESE WEEVIL adults (1267- 1897 [1555 peak] GDD50) feed on ash, cherry laurel, pyracantha, privet, rose, spirea, forsythia, lilac, barberry, flowering dogwood, broad-leaved evergreens, and others. This flightless weevil is light to dark brown and feeds during the day on new leaves, shoots and inner foliage, but drops to the ground when disturbed. Remove excessive mulch to prevent overly moist soils around susceptible plants. Entomopathogenic nematodes, Heterorhabditis and Steinernema spp., offer variable control of larvae in field plots but have performed better in container soil in greenhouses. Adult chemical control includes acephate, pyrethrins, piperonyl butoxide, and cyfluthrin and imidacloprid. The twobanded Japanese weevil is resistant to sevin and malathion.
DISEASES Bob Mulrooney Extension Plant Pathologist SLIME MOLDS continue to appear in mulched beds. These patches of white, pink or light yellow powdery masses can be found in mulch on stems of plants and other objects. These powdery masses are the reproductive stages of these fungi. The good news is-- they cause no harm to the plants. They can be dispersed with a strong stream from a garden hose or broken up with a rake. Slime molds are often called “dog vomit fungus,” which is fairly descriptive. HOLLYHOCK RUST is now very evident on susceptible cultivars. Numerous orange-red pustules can be seen on the underside of the leaves. The upper surface will be yellowed. If control is needed, spray with Immunox, Funginex, or Daconil for control.
UNIVERSITY OF DELAWARE
Acclaim extra and Drive are most effective when applied to young, actively growing crabgrass with good soil moisture. Herbicide applied under drought and/or heat stress may result in reduced control and increased potential for turfgrass injury. Apply with flat fan nozzles producing a fine spray droplet (avoid flood jets). You can apply these herbicides in combination with residual preemergence herbicides. However, residual herbicides applied late in the season may interfere with late summer/fall overseeding. Acclaim Extra: The rate of Acclaim Extra is dependent on turf species and crabgrass growth stage. Don't exceed 20 oz/A on well established Ky bluegrass (label states up to 28 oz/A) Tall and fine fescue and perennial ryegrass are very tolerant. At 20 oz/A Acclaim Extra is effective on crabgrass up to 2 tillers (in some cases up to 3-4 tillers).
Fornfomromrae tion i
(Continued)
on pests & practices covered in this newsletter, call your County Extension Office Helpful numbers to know: 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.
Weeds (Continued) Tank-mixing or applying Acclaim Extra prior to or following a broadleaf weed herbicide (especially 2,4-D and/or MCPP) may reduce weed control. The formulation contains an adjuvant but depending on application equipment, nonionic surfactant (NIS) may be needed. Drive: Safe on Kentucky bluegrass, perennial ryegrass and tall fescue. Consult the label for use on bentgrasses and fine fescue. Drive can be effective on 2-4 tillered crabgrass and active on large multi-tillered crabgrass when in its reproductive phase (visable seedheads). No goosegrass control. Drive is tank-mix compatible with broadleaf herbicides. Apply with methylated seed oil (MSO). Two formulations are available: Drive 75 DF and a new liquid formulation Drive XLR8 1.5 L (more consistent control in some studies). Combination Products: Q4, Quincept, and Onetime contain Drive in combination with broadleaf herbicides or in the case of Q4 also contain sulfentrazone for yellow nutsedge. Consult labels to determine if a spray adjuvant is recommended. Also determine the use rate of quinclorac (the active ingredient in Drive). Applying quinclorac at less than 0.75 lbs ai/A and/or without a spray adjuvant such as methylated seed oil may reduce the consistency of crabgrass control especially if the growth stage has exceeded one-tiller. Solitare: Contains quinclorac and sulfentrazone (the active in Dismiss) to control/suppress crabgrass and sedges as well as some broadleaf weeds. Looks promising due to potential synergy on crabgrass by using both herbicides together, but only in our 2nd year of testing. Sulfentrazone shows potential to control small (1-4 leaf) goosegrass. Editor: Susan Barton Extension Horticulturist
Cooperative Extension Townsend Hall Newark, Delaware 19717
, 20 09 July 7 AS OF
DEGREE
G GROWINDAYS
13 = 13 lege Col y, PA) 6 8) ore = 14 nt '08 rthm Cou e 83 ( Swa aware ous ) = 13 l wn y (De enh geto Gre Count eor her e r, G = NA) Fisc Castl 8 ente w c. C 495 ('0 (Ne Edu 1 h & nty) = u earc Res sex Co ( Su s
