Spring insecticide treatments control adelgids on Douglas fir

Varela, L. G.; Cowles, Richard S.; Donaldson, D. R.

doi:10.3733/ca.v050n05p34

Cited by 3 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Conditions are favorable for conserving natural enemies within Christmas tree plantations for IPM practice, with the exception of current practices for managing armored scales. Dormant application of horticultural oil has proven ineffective against armored scales in Christmas tree plantings and is phytotoxic to some tree species sensitive to oil, such as Douglas-Þr (Varela et al 1996). In Pennsylvania, growers spray three to four applications of dimethoate at a high labeled dosage at 3Ð 4-wk intervals (Heller and Kline 2005), a use that continues only due to a Special Local Needs registration (Brian Schildt, personal communication).…”

mentioning

confidence: 96%

Optimizing a Basal Bark Spray of Dinotefuran to Manage Armored Scales (Hemiptera: Diaspididae) in Christmas Tree Plantations

Cowles¹

2010

jnl. econ. entom.

Self Cite

View full text Add to dashboard Cite

The armored scales Fiorinia externa Ferris and Aspidiotus cryptomeriae Kuwana (Hemiptera: Diaspididae) are increasingly damaging to Christmas tree plantings in southern New England. The systemic insecticide dinotefuran was investigated for selectively suppressing armored scale populations relative to their natural enemies in cooperating growers' fields in 2008 and 2009. Banded soil application of dinotefuran resulted in poor control. However, a dinotefuran spray applied to the basal 25 cm of trunk resulted in its absorption through the bark, translocation to the foliage, and good efficacy. The basal bark spray did not significantly impact the activity of predators Chilocorus stigma (Say) or Cybocephalus nipponicus Enrody-Younga and in 2009 showed a dosage-dependent improvement in the percentage of scales parasitized by Encarsia citrina Craw. A field dosage-response factorial experiment revealed that a 0.25% (vol:vol) addition of a surfactant with dinotefuran did not enhance insecticidal effect. Probit-transformed scale population reduction relative to the untreated check was subjected to linear regression analysis; reduction of scale populations was proportional to the log of insecticide dosage, whereas basal bark spray efficacy declined in proportion to the cube of tree height. The regression equation can be used to optimize dosage relative to tree height. Excellent efficacy resulted from basal bark spray application dates of 28 April (prebud break) to mid-June, but earlier spray timing within that treatment window had fewer crawlers discoloring new growth with their short-lived feeding. A basal bark spray of dinotefuran is well suited for integration with natural enemies to manage armored scales in Christmas tree plantations.

show abstract

mentioning

confidence: 96%

Optimizing a Basal Bark Spray of Dinotefuran to Manage Armored Scales (Hemiptera: Diaspididae) in Christmas Tree Plantations

Cowles¹

2010

jnl. econ. entom.

Self Cite

View full text Add to dashboard Cite

show abstract

“…A slight yellowing on some leaves was noted for weeping hemlock (T. canadensis 'Sargentii'), but not the species form of T. canadensis. In other studies of conifers Douglas-fir was found to be sensitive to horticultural oil, as demonstrated by reproducible chlorosis among treated trees (Varela et al 1996), whereas true firs (Abies spp.) typically exhibit chlorosis of new growth if sprayed with oil during shoot elongation (Cowles, pers.…”

mentioning

confidence: 75%

Susceptibility of Chinese Hemlock (Tsuga chinensis) to Injury from Autumn Horticultural Oil Applications

Harper¹,

Cowles²

2013

AUF

View full text Add to dashboard Cite

Chinese hemlock (Tsuga chinensis) has been suggested as a possible replacement in landscape plantings for eastern hemlocks (T. canadensis), which are being lost due to infestations of hemlock woolly adelgid (Adelges tsugae). Chinese hemlock is highly resistant to hemlock woolly adelgid, but is a host for elongate hemlock scale (Fiorinia externa). Horticultural oil is a popular insecticide commonly used by professionals to manage various insect and mite pests of hemlock in landscapes, including hemlock woolly adelgid, spruce spider mite, and armored scales. In tests, horticultural oil applied in two separate autumn sprays was not phytotoxic to Chinese hemlocks. Therefore, 1% or 2% horticultural oil may be used to maintain Chinese hemlocks in landscape plantings.

show abstract

“…Until recently, the residual activity of most systemic insecticides was too short to affect multiple generations of aphids. Neonicotinyl compounds, however, can control sucking insect pests over several months when used as a soil-applied systemic (Varela et al 1996, Cowles andCheah 2002). It is especially intriguing that spring application of imidacloprid reduced the populations of sexuparae on trees (Table 1).…”

Section: Management Optionsmentioning

confidence: 99%

Management of balsam twig aphids in Christmas trees

Cowles¹

2003

Inspection of Feed Products and Pet Foods

View full text Add to dashboard Cite

Spring insecticide treatments control adelgids on Douglas fir

Abstract: Left, needle distortions caused by the Cooley spruce gall adelgid feeding on Douglas fir and white waxy material left by females. Above, yellow spots on the upper side of the needles are caused by adelgids feeding on the underside.

Cited by 3 publications

References 0 publications

Optimizing a Basal Bark Spray of Dinotefuran to Manage Armored Scales (Hemiptera: Diaspididae) in Christmas Tree Plantations

Optimizing a Basal Bark Spray of Dinotefuran to Manage Armored Scales (Hemiptera: Diaspididae) in Christmas Tree Plantations

Susceptibility of Chinese Hemlock (Tsuga chinensis) to Injury from Autumn Horticultural Oil Applications

Management of balsam twig aphids in Christmas trees

Contact Info

Product

Resources

About