You may have heard about integrated pest management (IPM) and wondered if it is something only farmers use. Actually IPM has a real place in any type of gardening, including your community garden plot. According to the UGA Integrated Pest Management website this is the definition of IPM:
It is a science-based decision making process that employs biological, mechanical, cultural, and chemical control methods in such a way as to minimize economic, environmental, and public health risks associated with pests and pest management practices.
Notice it is science-based decision making. This is important.
In practice, the gardener employs many different strategies to combat an insect pest or disease instead of just reaching for the chemical spray. For a very basic example a gardener wants to grow tomatoes knowing that Fusarium wilt can be a problem. (Fusarium wilt is a fungus that lives in the soil and infects plants through their root systems.) This gardener will employ IPM by:
Fusarium wilt on tomatoes. Photo from bugwood by William M. Brown, Jr.
making sure his/her soil is healthy
growing healthy plants using recommended fertilization and watering practices
learning about the Fusarium wilt fungus and its biology
choosing tomato cultivars that show resistance to Fusarium wilt – these will have the letter “F” after the cultivar name
caring for garden equipment by proper disinfection and not using equipment from another gardener that has not been disinfected
being aware of the hot, dry weather that favors Fusarium wilt and looking for wilting especially during these conditions
destroying any infected plants
practicing crop rotation
With IPM, actions are taken to prevent diseases and pests from becoming a problem. Rather than simply eliminating the pests that are found right now, using IPM means the gardener will look at environmental factors that affect the pest and its ability to do damage. Armed with this information, the gardener can create conditions that are unfavorable for the pest. Know your enemy!
Your local UGA Extension agent can help you make a positive disease or insect identification so that you can make a plan to deter the problem.
Aphids on tomatoes from bug wood. Photo by Brian Kunkel
Learning when and where an insect pest lays her eggs can help you find those eggs and remove them. Determining what weather conditions favor a disease can help you adjust your planting date to avoid the peak of the disease. Finding out how a disease is spread can also help you combat it. Is it soil-borne or are fungal spores spread with wind? Also, what beneficial insects prey on your insect pest and how can you attract those helpful insects?
Subscribing to this blog and other researched based information sources can help you know what diseases or pests are problematic in your area and what you can do about them.
If you haven’t visited the Upcoming Classes page of this blog, please do so. There are many classes and workshops coming up. Many are free and some are offered online.
There are currently three mistletoe elimination interventions, each delivering varying results. The three interventions are pruning infected tree branches, shoot pruning of mistletoe, and/or using a labeled chemical spray (ethephon). Note any specific commercial product mentioned here does not represent an endorsement, nor a statement of efficaciousness, but a summary of marketplace information at the time this publication was prepared.
Tree Pruning – Infection site branch pruning is a common means of controlling mistletoe. A twig or branch infected with mistletoe can be pruned at the nearest healthy originating node below an infection site. Do not tip, top, or use internode cuts on a twig or branch. (See Figure 11 in original publication online). The target node for pruning should be at least 14 inches below an infection site. Mistletoe infection site elimination through branch pruning should be treated as a proper pruning (Figure 12) or reduction cut (Figure 13, Figure 14, Figure 15). Figures in the original publication show proper cuts to be made at the next lowest branch node greater than 14 inches below an infection. Years will be needed for a tree to regain structural integrity after extensive mistletoe removal pruning.
Mistletoe Shoot Removal – One traditional treatment for mistletoe infection is to knock off brittle mistletoe stems from tree branches. Mistletoe stems snap off easy and nearly flush with branch bark, usually at the remnants of the holdfast leaving the haustorial cushion behind still within a branch. This treatment immediately reduces water loss from a tree, and reduces mistletoe reproduction. Unfortunately, simply knocking off mistletoe stems does not eliminate infections because the endophytic part of the mistletoe remains intact. It usually takes 1-3 years before mistletoe shoots noticeably reappear after removal. Approximately 80% of all pruned mistletoe stems re-grow and while without green shoots, become completely parasitic on a tree. Periodic mistletoe shoot removal may be a viable treatment on main stem infections where pruning is not practical.
A few studies have used a combination of mistletoe shoot removal and blocking light to the haustorial cushion. Light has been excluded from haustoria by various wraps, sprays, and applications like heavy pruning paint applications, aluminum foil, tin disks, tarpaper, tape, caulking, or black plastic. It is critical to not injure tree tissues around an infection site with any topical coating or through affixing any covering. Mistletoe shoot pruning and light exclusion from an infection site was thought to prevent new mistletoe shoot formation and starve haustoria embedded in tree branches. Generally, these types of mistletoe shoot stub treatment have not been found to be completely effective and so, not recommended in most circumstances.
Chemical Spray – (Note that pesticide information was correct as of August 2008 – labeled uses can change. Check the pesticide label for the most recent information!) Ethephon [(2-chloroethyl) phosphonic acid] acts as a mistletoe shoot abscission and defoliator by generating ethylene, a plant growth regulator. For example in one study, a 2% ethephon treatment applied to mistletoe shoots in the dormant season defoliated shoots in 75 days with no resprouting for 225 days, and with no negative impacts on the host. This treatment did not significantly impact the haustoria and new sprouts from the haustorial cushion area formed within 1-2 years.
Currently there is a chemical product labeled for mistletoe shoot control which contains this shoot abscission chemical (ethephon). This product is sold under the name FLOREL brand growth regulator, a trademark of the Rhone-Poulenc AG Company, and distributed by Monterey Lawn & Garden Products, Fresno, CA. [EPA Registration Number 54705-8]. Information for this publication regarding this product came from the company’s web site (accessed 8/29/2008). All label information was derived from the electronic version of the chemical product label.
The product as currently formulated contains 3.9% ethephon (0.33 lbs ethephon per gallon). The chemical is a highly acidic, colorless, odorless, clear liquid. This labeled product “… will cause the abscission of … leafy mistletoe shoots in ornamental deciduous trees.” Technically, this product is not labeled for leafy mistletoe removal from evergreen trees. Note a wide variety of other concentrations and application methods have been used in past research papers.
This ethephon product should be sprayed directly on mistletoe clumps until foliage and stems are wet.
Timing is crucial to prevent tree damage. Spraying should be completed after Fall leaf drop and before tree bud burst in Spring when daytime temperatures are above 65oF. Mix the product following all label directions. For example, under current label mixing instructions, mix one quart of product in 2 gallons of water for 5400 ppm concentration. Use of a surfactant is recommended. Spray only when no rain is forecast for a minimum of 24 hours. Return to and re-spray large clumps of mistletoe in one week. Because only the mistletoe shoot is impacted, retreat every 3-4 years. Mix and spray this product immediately. Do not store the mixed spray liquid for more than a few hours. Care is needed to prevent over-spray from staining or etching hardscapes or damaging painted surfaces.
Remember to carefully read and review the product label for your personal safety, safety of other living things, and the legal context of product use. Do not use this product near individuals or habitats of protected species, some of which could be around the tree site or on the tree exterior.
