CELEBRATING 26 YEARS! Welcome to my weekly series! THE LANDSCAPE ASK PROFESSIONAL Linda K. Lillie of Sprigs &Twigs Linda K. Lilie has beon Prosident of Sprigs & Twigs, Inc. for the last 26 years. She is a graduate of Connecticut College in Botany, an accredited NOFA Organic Land Care Professional, a Connecticut Master Gardener and a national award winning landscape designer for her design and installation projects. A long time ago, my grandmother told me she used something called "dormant oil" to control insects on her fruit trees. What is that and is it still effective?.Dawn Dormant oils have been around for centuries and are extremely effective in kiling insect pests on plants. shrubs and trees Back in your grandmother's day, "dormant oils were heavy oils that weren't as highly refined as they are today. Back then, dormant oils were generally limited to frut tree applications before bud break Today. there are a number of safe, highly refined oils used at different times of the year depending on the insect pest Dormant oils are much safer to humans and the environment than synthetic pesticides that are on the market today. Scientists also believe that dormant oils are more effective that synthetic pesticides because insects have not developed a resistance to them While ols don't work for all pests or on all plants. they are effective in a wide range of applications Today these highly refined oils are generally referred to as "horticultural" oils and originate from various petroleum, vegetable and animal-based sources. Allof the oils are effective in the same way. they either suffocate the insects or penetrate the cells of the insects. In either case, you must be able to see the insect or the eggs and directly apply the oil for it to be effective. You may also need to apply it multiple times. The fact that ols are drectly applied to insects to suffocate them also means that the ols are not harmful to humans like chemical pesticides which kill pests through disruption of metabolic processes. Horticultural oils kill powdery mildew, aphids. whiteflies, mites, scale insects, leafhoppers and a host of other pests Horticultural oils need to be applied when the temperature is above 40 degrees and no freezing is expected before bud swelling and bud break twhen the plant is domant). There are some oils that can also be used as folar treatments in the summer, so read the labels carefully for your specific application. Horticultural oils are not a silver bullet". Some plants are susceptible to injury from horticultural oils so you should be cautious and read labels carefully. These plants include: hickories, maples. lespecially japanese and red maple). black walnut, smoke tree, redbud junipers, cedars, spruce especially dwarf alberta spruce), plume cedar and douglas firs Horticultural oils should not be used on plants that are blue in color like blue hosta or blue spruce because they get their color from a waxy coating that could be removed by the oil which would cause the blue color to turn green Sprigs D&[wigs EMAIL OR MAIL YOUR QUESTIONS TO: info@sprigsandtwigs.net or Linda Lillie, Sprigs & Twigs Inc, PO Box 245, Gales Ferry, CT 06335 best SPRIGS & TWIGS VOTED THE BEST BY DAY READERS EVERY YEAR! CELEBRATING 26 YEARS! Welcome to my weekly series! THE LANDSCAPE ASK PROFESSIONAL Linda K. Lillie of Sprigs &Twigs Linda K. Lilie has beon Prosident of Sprigs & Twigs, Inc. for the last 26 years. She is a graduate of Connecticut College in Botany, an accredited NOFA Organic Land Care Professional, a Connecticut Master Gardener and a national award winning landscape designer for her design and installation projects. A long time ago, my grandmother told me she used something called "dormant oil" to control insects on her fruit trees. What is that and is it still effective?.Dawn Dormant oils have been around for centuries and are extremely effective in kiling insect pests on plants. shrubs and trees Back in your grandmother's day, "dormant oils were heavy oils that weren't as highly refined as they are today. Back then, dormant oils were generally limited to frut tree applications before bud break Today. there are a number of safe, highly refined oils used at different times of the year depending on the insect pest Dormant oils are much safer to humans and the environment than synthetic pesticides that are on the market today. Scientists also believe that dormant oils are more effective that synthetic pesticides because insects have not developed a resistance to them While ols don't work for all pests or on all plants. they are effective in a wide range of applications Today these highly refined oils are generally referred to as "horticultural" oils and originate from various petroleum, vegetable and animal-based sources. Allof the oils are effective in the same way. they either suffocate the insects or penetrate the cells of the insects. In either case, you must be able to see the insect or the eggs and directly apply the oil for it to be effective. You may also need to apply it multiple times. The fact that ols are drectly applied to insects to suffocate them also means that the ols are not harmful to humans like chemical pesticides which kill pests through disruption of metabolic processes. Horticultural oils kill powdery mildew, aphids. whiteflies, mites, scale insects, leafhoppers and a host of other pests Horticultural oils need to be applied when the temperature is above 40 degrees and no freezing is expected before bud swelling and bud break twhen the plant is domant). There are some oils that can also be used as folar treatments in the summer, so read the labels carefully for your specific application. Horticultural oils are not a silver bullet". Some plants are susceptible to injury from horticultural oils so you should be cautious and read labels carefully. These plants include: hickories, maples. lespecially japanese and red maple). black walnut, smoke tree, redbud junipers, cedars, spruce especially dwarf alberta spruce), plume cedar and douglas firs Horticultural oils should not be used on plants that are blue in color like blue hosta or blue spruce because they get their color from a waxy coating that could be removed by the oil which would cause the blue color to turn green Sprigs D&[wigs EMAIL OR MAIL YOUR QUESTIONS TO: info@sprigsandtwigs.net or Linda Lillie, Sprigs & Twigs Inc, PO Box 245, Gales Ferry, CT 06335 best SPRIGS & TWIGS VOTED THE BEST BY DAY READERS EVERY YEAR!