A Newsletter for Professionals Growing Greenhouse Crops in the Rocky Mountain Region

Contents

• Colorado State University Seventh Annual Poinsettia Cultivar Evaluation
• EPA Reveals Process to Continue Using Fumigant
• Pests to Worry About When It's Cool

Join us for our Sixth Annual Poinsettia Cultivar Evaluation on Tuesday, December 4, 2001 from 9:00 a.m. to 3:00 p.m. at the W.D. Holley Plant Environmental Research Center on the Colorado State University Campus, Fort Collins, Colorado.

Don’t miss this opportunity to compare and evaluate new and old poinsettia cultivars under Colorado conditions. Examine several interesting reds, whites, pinks, and novelties that have not been seen before in Colorado. Many of these are experimental cultivars offered by the breeding companies and may be available in the future. You will see more than 100 cultivars from the Paul Ecke Ranch, Fischer USA, Dümmen Young Plants and HMA. View cultivars, discuss poinsettia production issues, and view current poinsettia research and student research projects.

Download the Brochure (Adobe Acrobat Reader required)

For further information, Contact:
Dr. Steven Newman
(970) 491-7118

The Society of American Florists (SAF) and several floral industry leaders recently heard what steps growers may need to take to continue using methyl bromide after the chemical's phase-out in 2005. The fumigant is used in growing many crops and in interstate and international trade.

Under U.S. law and in accordance with international treaty obligations, methyl bromide is scheduled for 100 percent phase-out by 2005, with a 50 percent reduction effective January 2001, and a 70 percent reduction scheduled for 2003. Developing nations cut continue using methyl bromide until at least 2015, putting U.S. growers at a severe competitive disadvantage.

The Environmental Protection Agency (EPA) outlined the application process for obtaining critical use exemption" status during a two-hour conference call. Representatives from the U.S. Department of Agriculture also participated.

Users will be able to apply for a "critical use" exemption if they meet certain criteria, including significant market disruption and the lack of available alternatives, among other things. Many points outlined by the EPA were very complex, and growers were concerned particularly about who would receive exemptions, and what information would be required in the process.

The EPA plans to begin accepting applications for review in early 2002. It will then forward applications to an international governing body for final approval by 2003.

SAF will continue to work with the Crop Protection Coalition, the coalition of affected agricultural users of methyl bromide, and with the California Cut Flower Commission, the Florida Nurserymen and Growers Association and other interacted users on the critical use exemption issue.

For further information, Contact SAF's:
Lin Schmale
(800) 336-4743

This is a summary of Dr. Richard Linquist's presentation at the 2001 Rocky Mountain Greenhouse Short Course (sponsored by: Olympic Horticultural Products)

Temperature Effects on Insects and Mites

• Insects & Mites are “cold-blooded” animals affected by temperature: feeding, reproduction, development time & survival
• Temperature is the most important factor in insect & mite development: slower at cool temperatures, faster at warm temperatures

  Temperature and Spider Mite Development (data from Sabelis, 1981)

  • Egg to adult in 28.2 days at temperature range of 50° - 68°F
  • Egg to adult in 8.3 days at temperature range of 77° - 95°F

  

  Effect of Temperature on Spider Mite Increase

  • One month @ 60°F: 20 mites from 1 female
  • One month @ 70°F: 12,000 mites from 1 female
  • One month @ 80°F: 13,000,000 mites from 1 female

   

  Greenhouse insects and mites that may create problems even at cool temperatures

  Aphids

  • Nymph to adult in 7-10 days They do very well in cool conditions
  • Best chemicals: AZA (Azatin, Ornazin), Endeavor, Marathon (G,WP,II), Closure, Mesurol, DuraGuard, Orthene, Thiodan, Oils, Insecticidal Soaps
  • Biological controls: Beauveria bassiana (3-5 applications at 5-7 day intervals); several parasitoids and predators available

  Aphids on Easter lily recently moved from cooler

  Fungus Gnats

  • Egg to adult in 21-28 days
  • Treat during first 10 days. If necessary, repeat in 25-30 days
  • Best chemicals: Adept*, AZA (Azatin, Ornazin)*, Distance*, Citation*, DuraGuard, Marathon (*Insect growth regulators that affect only larvae )
    
  • Biological controls: Nematodes, Mites

    	Larvae will cause damage to roots
    Poinsettia cutting root damage from fungus gnat larvae

  
  Shore Flies

  Egg to adult in 12-14 days Reduce algae (Key to control) Best chemicals: DuraGuard Adept*, Distance*, Citation*, (Conserve? Soap? for adults) (*Insect growth regulators that affect only larvae ) Biological controls: Nothing available commercially.

  Whiteflies

  Silver Leaf Whitefly: Egg to adult in 25-35 days Best chemicals: Distance, Endeavor*, Marathon (G,WP,II)*, Sanmite, Oils, Insecticidal Soaps (*Systemic or translaminar products) Biological controls: Parasitoids, predators, Beauveria bassiana

  Western Flower Thrips

  Egg to adult in 12-45 days Best chemicals: Avid (+ oil or AZA),Thiodan + Pyrethroid, Orthene, Marathon II, Mesurol, Closure, Conserve (2-3 applications at 5-7 day intervals, except Orthene & MII) Biological controls: Beauveria bassiana + AZA (3-5 applications at 5-7 day intervals), Predatory mites Adding sugar may help some products

  More Precise Information on Pest Development: Degree Days

What are Day Degrees

• Insects and mites have lower (and upper) temperature limit for development – varies with species
• Day degrees measure the difference between minimum development temperature and the average daily temperature
• Knowing total day degrees for pest development helps track generation time(s)

Calculating Degree Days

• (Max temp + Min temp) / 2 = Average temp
• Average temp – development threshold for pest = day degrees
• If average temperature is LESS than the pest’s development threshold, the day degree value is 0

Real numbers

• Max 78 + min 54 = 132 / 2 = 66 (average)
• If pest has development threshold of 50°F, then 66 – 50 = 16 day degrees
• If we know the total day degrees to go from egg to adult, we can estimate the generation times for pests by adding day degrees over time

Pests more likely to be a problem at cooler temperatures

• Low temperature threshold for development (below 50°F)
  • Range for pests 39-55°F
• Relatively few day degrees needed to complete development (less than 250)
  • Range for pests 196-1216

Where to go for more information

University of California Statewide Integrated Pest Management Project

Integrated Pest Management for Floriculture and Nurseries
University of California Division of Agriculture and Natural Resources
Publication 3402