Management of Potato Leafhopper and Maple Spider Mite on Nursery Grown Maples

<p>Potato leafhopper <em>Empoasca fabae</em> (Harris) (Homoptera: Cicadellidae) and maple spider mite <em>Oligonychus aceris</em> (Shimer) (Acarina: Tetranychidae) are important pests of maple trees. Investigations determined how insecticide use and fertilization impacted the abundance of <em>E. fabae</em> and <em>O. aceris</em> on `Red Sunset' red maple and `Autumn Blaze' Freeman maples. Bifenthrin applications directed against leafhoppers reduced damage to both cultivars, but increased <em>O. aceris</em> on Autumn Blaze. Using a threshold of one leafhopper per branch to trigger pesticide applications protected Red Sunset maples from leafhopper injury. It also prevented outbreaks of <em>O. aceris</em> on Autumn Blaze because few trees reached this density. Two phytoseiid mites, <em>Neoseiulus fallacis</em> (Garman) and <em>Typhlodromus caudiglans</em> (Schuster) (Acarina: Phytoseiidae), and one stigmaeid, <em>Zetzellia mali</em> (Ewing) (Acarina: Stigmaeidae) were identified as predators of <em>O. aceris</em> on maple leaves. Populations of <em>Z. mali</em> were higher in both years on Red Sunset than Autumn Blaze. Fertilizer applications on field grown maples increased populations of leafhoppers and spider mites. More damage by <em>E. fabae</em> was observed on fertilized Red Sunset than on fertilized Autumn Blaze trees. <em>O. aceris</em> populations were higher on fertilized Autumn Blaze than fertilized Red Sunset trees. <em>O. aceris</em> populations were positively correlated with nitrogen content in the leaves in both cultivars. Mite populations increased at a lower rate with increasing concentration of nitrogen in the leaves of Red Sunset than on those of Autumn Blaze maples. Differences may be explained by a greater abundance of <em>Z. mali</em> (Ewing) on Red Sunset maples. In laboratory experiments <em>N. fallacis</em> consumed significantly more protonymphs and adults of <em>O. aceris</em>, whereas <em>Z. mali</em> consumed more eggs. <em>N. fallacis</em> consumed more <em>Z. mali</em> on Autumn Blaze than on Red Sunset maple. <em>Z. mali</em> consumed fewer <em>N. fallacis</em> on both maple cultivars than <em>O. aceris</em>. Leaf domatia on Red Sunset leaves provide refugia for <em>Z. mali</em> predators. Absence of leaf domatia on Autumn Blaze left <em>Z. mali</em> no place to hide from <em>N. fallacis and diminished their contribution to <em>O. aceris</em> mortality Thus, differential susceptibility of these cultivars to spider mites is mediated by the capacity of leaf domatia to influence intraguild predation among phtyoseiid and stigmaeid predators. </em></p>

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Entomology

Year

2013

Author dc:creator

• Prado Beltran, Julia

Contributors dc:contributor

• Clifford S. Sadof
• Ricky E. Foster
• Ian Kaplan
• Michael V. Mickelbart
• Roberto G. Lopez

• autumn blaze
• maple spider mite
• maple trees
• potato leafhopper
• red sunset
• Agricultural Science
• Agriculture
• Entomology
• Horticulture

Repository record dc:identifier

https://docs.lib.purdue.edu/open_access_dissertations/73

OAI identifier oai:identifier

oai:docs.lib.purdue.edu:open_access_dissertations-1142