MECHANICAL AND PHYSICAL CONTROL Flashcards
Land Preparation
Well prepared sites are easier to irrigate and manage, resulting in better weed control and fewer diseases.
It also reduces soil compaction and contribute to good soil drainage.
Considerations: Soil depth, texture, topography, and site surveying for the presence of weeds and pests. Preplant treatments can overcome pests before the crop is ever even planted.
Soil Tillage
Contribute by killing weeds and can disrupt pest lifecycle’s if performed with pesticides.
Also performed to incorporate fertilizer and improve H20 penetration.
Proper timing is necessary so as not to support weed growth.
Different kinds of attachments are used for different kinds of crops for instance the moldboard plow would not be used in the same scenarios as the French plow.
Deep plowing is used to bury certain weed seed species up to 10-12in. in depth to render them futile.
Tillage in many cases can have the opposite effect; for this reason many farmers have taken on low-till (ridge till, strip till, mulch till)/no-till/conservation till systems.
Mowing
Is an effective weed management tool, particularly when used in combination with other management methods.
Most common method of nonchemical weed control used along rights-of-way.
Proper timing and site conditions are important factors.
Should be completed before weeds set seeds or before seeds mature and when soil moisture is low.
Should be avoided when pest migration to crops could be harmful such as late blooms.
Correct height and frequency is critical for preventing invasion in turf.
Flaming
A weed management technique used in row crops, orchards, roadsides, and industrial sites. Flaming commonly uses propane burners however hot water, steam, or infrared light is also available. Flaming is most effective on young annual dicot weeds. Young perennial weeds are also susceptible but require more than one treatment.
Burning
Most usually applied in forest land control, examples have been used in the passed against stem and sheath spot in rice, with considerable success.
Due to recent legislation however, burning is to be substantially due to air pollution.
Mulch
Is a layer of material covering the soil surface.
Used extensively in landscapes and crop production for weed control, additionally conserve soil moisture, and help maintain uniform soil temperatures.
Plastic mulches are a common practice in the strawberry industry.
Available as wood chips, bark, green waste, polyethylenes, etc.Sometimes used together.
Best applied in the spring when soils are weed free.
Unfortunately mulches can sometimes host other pests such as snails, slugs, earwigs, ants, sowbugs, invertebrates and other vertebrates.
Soil Solarization
Involves covering moist soil with clear plastic film and allowing the soil to heat up for 3-6 weeks before planting the crop.
This practice reduces or eliminates many soil-inhabiting pests and weeds by raising the temperature in the top 2-3inches to lethal levels. In addition this causes changes in favor of the beneficial soil microflora resulting to increased yields and improved crop quality.
Temperature Manipulation
Widely used in the soil media for greenhouse and nursery operations for the control of many insect, weed, nematode, and pathogen pests.
Heating or steaming to a temperature of 158 Farenheit kills most plant pathogens; nematodes tend to perish around 123 Farenheit for over 30 minutes. Long exposure to high temperature however can produce undesirable effects such as the break down of soil structure.
To avoid this, soil pasteurization is used as opposed to sterilization, where less intensive/shorter duration treatments are made at lower temperatures.
Cold storage is used in many post harvest situations with the same desired effect of eliminating ride along pest such as apple maggot in apples.
Traps
Are devices for controlling many vertebrate and invertebrate pests.
Some of these such as sticky traps are used for monitoring purposes.
