THE INFLUENCE OF CROP PHYLODIVERSITY ON HERBIVOROUS INSECTS OF SQUASH AND THEIR NATURAL ENEMIES

Open Access
- Author:
- Coco, Angela M
- Graduate Program:
- Entomology
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- May 10, 2019
- Committee Members:
- John F Tooker, Thesis Advisor/Co-Advisor
Shelby Jay Fleischer, Committee Member
Beth Krueger Gugino, Committee Member - Keywords:
- ecology
entomology
biology
squash
butternut
evolution
phylogeny
insect
plant
interaction
structure
volatile
ipm
cues
response
behavior
parasite
parasitoid
Centistes diabroticae
Celatoria setosa
nematode
gregarine
coco
angela
tooker
john
kaplan
ian
rock springs
agriculture
vegitable
crop
intercrop
polyculture
herbiore
pest
phytophageous
bug
cucumber beetle
squash bug
wasp
fly
food
integrated
management
cucurbit
balduf
community
phylogenetic
relatedness
neighbor
divergence
zucchini
associational
resistance
apparency
research
thesis
2017
2018
2019
regression
elytron
length
sticky
pitfall
trap
foliage
flower
scout
scouting
rain
natural
enemies
diversity
merkle
control
eastern
north
america - Abstract:
- Herbivorous insects can be problematic for growers. Despite regular use of insecticides to manage their populations, these insects can still cause extensive damage to crops. Integrated Pest Management (IPM) was developed as an alternative to regular insecticide use to manage insects. One IPM-based tactic, intercropping, is known to reduce herbivorous insect abundance and damage in fields. Because the diet of many herbivores is restricted to only closely related taxa with similar chemistry, diverse plant communities can interfere with their ability to find suitable hosts via associational resistance. The effectiveness of intercropping against herbivorous insects may depend on the phylogenetic relatedness of neighboring crops. In my first chapter, I studied in a vegetable cropping system how evolutionary divergence times among plant species influenced the effects of associational resistance on the insect community. With butternut squash as a focal crop in a series of different intercropping combinations, I found that the phylogenetic divergence of neighboring plants had an inconsistent effect on the abundance of herbivorous insects and others (predators, parasitoids, pollinators, detritivores). When considering relationships between crop plants and their insect community, my results suggest that the phylogenetic relatedness of neighboring plants might be one of the mechanisms driving associational resistance against herbivorous insects but more research is needed. In my second chapter, I explored parasites and parasitoids of the striped cucumber beetle (Acalymma vittatum), an economically important pest of cucurbit crops in eastern North America. I identified several parasitoids and parasites (Celatoria setosa, Centistes diabroticae, Howardula spp, Nematomorpha, Gregarinasina) and revealed some details on their ecology related to date, beetle size, and beetle gender. I also found that the striped cucumber beetle and its parasites appeared to share a density-dependent relationship to one another, and that the phylodiversity of neighboring crops may have indirectly influenced parasitism of striped cucumber beetles.