Tag Archives: Natural Insect and Disease Control

Natural Insect and Disease Control: Devil’s Shoestring

Natural Insect and Disease Control:

Devil’s Shoestring: Tephrosia virginiana.

Devil’s shoestring got its name from voodoo and witchcraft. It was used to “trip up” the devil and keep him from your door.

There are about 19 species of this North American native weed and much confusion over how they look with many being called Devil’s shoestring and being described as a big clump of grass or more like a vine. This member of the viburnum family has a valuable natural insecticidal property to it. Although low in toxicity to animals, it is regarded as poisonous to fish. Wild turkeys however love to eat it.

Resembling a large clump of grass growing in the open and in light shade on limestone slopes and cliffs, the roots contain the popular natural insecticide ingredient rotenone and can be used by making a strong tea of them, straining it with a coffee filter and then spraying it onto infested plants with a spray bottle.

Also known as rabbit bean, turkey pea, goat’s rue and hoary pea, Native Americans used it for medicinal purposes and to poison fish. It prefers well-drained sandy soils. The photo above is known most commonly as goat’s rue.

Also read about how to get rid of thistles naturally in this month’s archived articles.

Natural Insect and Disease Control: Powdery Mildew.

Natural Insect and Disease Control:

Powdery Mildew affects a wide variety of plants, usually in high humidity areas, and is caused by a any variety of fungi in the order Erysiphales. It’s also one of the easiest diseases to diagnose since the white powdery spots on the leaves or stems of an infected plant are very distinctive.

Powdery mildew is unattractive and it can affect the flavor and reduce yields of some fruits and vegetables. Although plants are unsightly and can be weakened by an infection, they do not usually die. Powdery mildew on ornamentals is an aesthetic issue, and not usually worth treating. Prevention and control is more important for vegetables.

Powdery mildew of wheat thrives in cool, humid climates and proliferates in cloudy weather conditions. The pathogen can also be an issue in drier climates if wheat fields are irrigated. Ideal temperatures for growth and reproduction of the pathogen are between 60 °F (16 °C) and 70 °F (21 °C) with growth ceasing above 77 °F (25 °C). Dense, genetically similar plantings provide opportune conditions for growth.


Milk has been popular with home gardeners and small-scale organic growers as a treatment for powdery mildew. Diluted 1:9 (1 part milk to 9 parts water) and sprayed on susceptible plants at the first sign of infection, or as a preventative measure, with repeated weekly application often controlling or eliminating the disease. Any milk can be used, even skim milk. Studies have shown milk’s effectiveness as comparable to some conventional fungicides, and better than benomyl and fenarimol at higher concentrations. Milk has proven effective in treating powdery mildew of summer squash, pumpkin, grapes and roses.
New Zealand also found out about this new cure and has started to see changes on the grapes that are used for wine production.

Spraying leaves with baking soda (1 teaspoon in 1 quart water) raises the pH, creating an inhospitable environment for powdery mildew.

 

Natural Insect and Disease Control: Mosaic Virus:


Natural Insect and Disease Control:

Mosaic Virus:
Unlike fungicidal chemicals used to control fungal diseases, to date there are no efficient chemical treatments that protect plant parts from virus infection. Additionally, there are no known chemical treatments used under field conditions that eliminate viral infections from plant tissues once they do occur. Practically speaking, plants infected by viruses remain so. Thus, control of tobacco mosaic virus is primarily focused on reducing and eliminating sources of the virus and limiting the spread by insects. Tobacco mosaic virus is the most persistent plant virus known. It has been known to survive up to 50 years in dried plant parts. Therefore, sanitation is the single most important practice in controlling tobacco mosaic virus.

Control for Seedling Growers and Gardeners
The most common method of transferring the virus from plant to plant is on contaminated hands and tools. The most common sources of virus inoculum for tobacco mosaic virus are the debris of infected plants that remains in the soil and certain infected tobacco products that contaminate workers hands. Cigars, cigarettes, and pipe tobaccos can be infected with tobacco mosaic virus. Handling these smoking materials contaminates the hands, and subsequent handling of plants results in a transmission of the virus. Therefore, do not smoke while handling or transplanting plants. Workers who transplant seedlings should refrain from smoking during transplanting and wash their hands frequently and thoroughly with soap and water. Tools used in transplanting can be placed in boiling water for 5 minutes and then washed with a strong soap or detergent solution. Dipping tools in household bleach is not effective for virus decontamination. Any seedlings that appear to have mosaic symptoms or are stunted and distorted should be removed and destroyed. After removing diseased plants, never handle healthy plants without washing hands and decontaminating tools used to remove diseased plants.
Persons purchasing small tomato plants for transplanting should beware of any plants showing mottling, dwarfing, or stunting. Avoid the purchase of any affected plant. Gardeners are advised to follow the same procedures recommended for greenhouse workers when handling tomato transplants. Other control methods for home gardeners include roguing (removal of diseased plants), destruction of diseased and infected plants, and control of weeds and chewing insects. When roguing and destroying mature diseased plants from the home garden, be sure to wash hands and decontaminate any tools used in the process before contacting healthy plants.
Common plant hosts for the mosaic virus are tomato, potato, pepper, petunia, snapdragon, delphinium, and marigold. Tobacco mosaic virus also has been reported to a lesser extent in muskmelon, cucumber, squash, spinach, celosia, impatiens, ground cherry, phlox, zinnia, certain types of ivy, plantain, night shade, and jimson weed. Although tobacco mosaic virus may infect many other types of plants, it generally is restricted to plants that are grown in seedbeds and transplanted or plants that are handled frequently.