Drought and Fertilizer: How Two Mainstays of Summer Bring in the Bugs

In the middle of the hot summer, insect populations build to increasingly damaging levels. Pest control becomes harder this time of the season, and two key little-known issues arise for herbivorous insect control.

Drought: Plant stress due to heat and drought can lead to higher herbivore numbers, especially if that stress is intermittent. For example, let’s say you have a shrub, and aphids really like that shrub. You do not water it regularly, and the plant lives outside in the heat of the summer. The weather has stayed dry for a while, and your shrub is starting to stress. Sap feeders like aphids do not usually respond well to drought, because plant sap is powered by turgor pressure, and the sap must move for them to eat. No rain, no food. However, leafy plants produce more nitrogen in times of stress. Your dry, stressed plant produces tons of nitrogen and then (viola!) it rains. The aphids suddenly have everything they need to produce tons of baby aphids.

Fertilizers: Nitrogen fertilizers are generally applied to improve plant growth and help them cope with biotic and abiotic stresses. However, although maintaining plant health is the first line of defense against herbivore attack, trees that are over fertilized are often more vulnerable. This occurs by improving plant nutrition for herbivores. Just as nitrogen is essential for plant growth, it also increases herbivore growth. Therefore, plant tissue that is high in nitrogen due to fertilization makes herbivorous pests grow faster and reproduce more. Fertilizer also benefits herbivores by reducing plant defenses. This happens because nitrogen stimulates rapid plant growth which requires all the carbon fixed through photo-synthesis to be used for plant tissue instead of defensive chemicals. Therefore, plants do not build chemicals toxic to herbivores or chemicals that attract natural enemies such as parasitoids to help defend themselves. Therefore, be sure to calibrate fertilizer application equipment, and do not apply more fertilizer than is recommended or necessary to maintain plant quality.

From: Steve Frank, NCSU Extension Entomologist

Bullington Center: Mid-Summer Plant Sale

ONE DAY ONLY! Saturday July 16th, 2011. 10:00am - 4:00pm

Come see the hand-selected inventory of plants for sale at this special summer event. Examples of plants now in bloom include coneflower, rudbeckia, daylilies, Rozanne geranium, hosta and many more.
For more information of to inquire about a specific plant, call (828)698-6104. See you there.

Squash Bugs Present by the Hundreds in Henderson County Gardens

These pests of vegetable gardens usually hide under leaves or around the base of plants. They characteristically shy away or move to cover when approached.

All cucurbit vine crops are subject to squash bug infection. The bugs prefer squash, pumpkin, cucumber, and melon, in that order.

Feeding in colonies, adults and nymphs pierce vines with their needle-like mouthparts. While feeding, they inject a toxic substance into plants. As a result, vines quickly turn black and dry out. This aspect of squash bug damage superficially resembles bacterial wilt symptoms. When infestations are heavy, fruit may not form.

Squash bugs overwinter as adults under plant debris or other suitable shelter. When cucurbit vines start to run in spring, squash bugs fly into gardens and mate. Over a period of several weeks, eggs are laid on undersides of leaves, typically in the angles formed by leaf veins. One or 2 weeks later, depending on the temperature, nymphs hatch from the eggs and begin to feed.

In small gardens, adult squash bugs and leaves with egg masses can be handpicked and destroyed. The bugs can also be trapped by placing small boards near the host vines. Squash bugs gather under the boards at night and are easily collected and destroyed the next morning.

Should a significant infestation develop, insecticide recommendations and rates can be found in the current North Carolina Agricultural Chemicals Manual.

Non-native and Invasive Forest Plants Workshops for Landowners

The Non-native and Invasive Forest Plants Workshops for Landowners is a series of 6 one-day educational workshops featuring presentations by experts in non-native invasive plants that impact North Carolina’s forests. Each workshop will engage regionally based stakeholder groups in the planning and educational content.

What you will learn

• What are non-native and invasive species, and why should you care?
• Identification of specific problem species
• The impacts of these plants on forest communities (ecologic, economic and cultural)
• How non-native species are introduced
• What are the risks of the “do-nothing” style of management
• Gain exposure to organized NNI stakeholder groups and efforts currently taking shape, or ongoing, in your region
• Resources available to landowners and what steps you can take
• How your neighbors and local professionals are dealing with NNI challenges.

Workshop Regional Locations and Dates

• Sandhills, Lower Piedmont and Uwharries:
  August 19, 2011 - Moore County Extension Center
  707 Pinehurst Ave, Agricultural Center, Carthage, NC 28327
  
• Western North Carolina:
  September 13, 2011 - Crowne Plaza Tennis & Golf Resort
  One Resort Drive, Asheville, NC 28806
• Coastal Plain of North Carolina:
  October 18, 2011 - Duplin County Extension Ctr.
  165 Agriculture Drive, Kenansville, NC 28349
  
• Northeastern North Carolina:
  February 7, 2012 - Sen. Bob Martin Eastern Ag Center
  2900 NC Highway 125 South, Williamston, NC 27892
• Piedmont (includes urban forestry topics):
  May 1, 2012 - Bur-Mil Park,
  5834 Bur-Mil Club Rd., Greensboro, NC 27410
• Northern Blue Ridge:
  May 8, 2012 - Wilkes County Community College,
  1328 S. Collegiate Drive, Wilkesboro, NC 28697

Advanced registration for these workshops is required. Need more information? Online registration form CLICK HERE or Contact the NCSU Forestry and Environmental Outreach Program at 919-515-9563, or by email: forestry_outreach@ncsu.edu