by Jan Hughes
However, I was not prepared when a swarm of honeybees took up residence in an old wine barrel on my patio, located close to our sliding door. As much as I love them, this was not the place for them to live!
Initially, I called a friend whose husband keeps a couple of hives on their property. He graciously came over to evaluate the situation. He could not help me as he did not have an empty hive to transfer these bees to and he was not sure how we could even get them out of the barrel with that tiny opening. He gave me several sources to explore which was very helpful.
I put out the SOS and eventually connected with another beekeeper who would come out that evening! (As you know, bees are like chickens in that they go back into the hive each night. So, we had to wait until dusk to have the best chance for getting them all confined.)
Once he got home, he placed the barrel in his yard close to his other bees, uncovered the hole and left them to acclimate….
Success! It seems it was a win-win for all of us! I even got my barrel back and a jar of his homegrown honey out of the deal!
Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.
Photo credits: Jan Hughes
Melody Kendall
The best way to control pests in the garden is to put the right plant in the right place, declutter your landscape, create barriers, use mulch and, we talked about this last week, encourage the natural enemy populations in your gardens.
Enter the integrated pest management method of pest control. Integrated pest management (IPM) is a science-based approach to managing pests using more environmentally friendly methods. IPM is a process that you can use to solve pest problems while minimizing risks to people and the environment. It can be used to manage all kinds of pests in urban, agricultural, and wildland or natural areas.
When looking for pest management solutions, prevention is the key. Healthy plants are the best defense against pests. Provide plants with proper fertilization, irrigation, and other practices that support vigorous growth. Healthy plants can tolerate a certain amount of damage from pests and may not need to be treated. If you have a plant that's not doing well, sometimes the best solution can be to remove it and plant it somewhere else. Remember to plant the right plant, in the right place, under the right climate conditions. Before purchasing a plant, be sure to check for any insects and disease they are prone to harbor.
When problems develop, identifying the pest or problem is the first and most important step. Once you have identified your pest or problem, you can proceed to assess management options. Is it caused by an insect pest, a vertebrate pest or maybe a disease or perhaps it is an abiotic problem? All this information is essential to planning your attack. Once you have identified your problem you can research solutions.
The key to identification is observation and this UC IPM link http://ipm.ucanr.edu/PMG/PESTNOTES/index.html can help with this identification process. Following the prompts you can discover your pest and learn about what IPM options to use. These options will be listed from cultural controls, e.g. creating barriers and use of mulch to the least toxic chemical controls. Getting information from other knowledgeable experts like your local UC Master Gardeners is a good strategy as well. Once your pest ID is established you can proceed with the correct control method.
If the purchase of pesticides is the correct method, always make sure to read the label. This UC IPM link covers it all http://ipm.ucanr.edu/PMG/PESTNOTES/pn74126.html . The label will give you all the information you will need to make that final purchase. Be sure the type of plant or site you plan to treat is listed on the label. Do not to use pesticides labeled for use on ornamental plants on plants that will be consumed. Don't use pesticides labeled for outdoor use indoors and remember that pesticides can seriously damage some plants; read the label to be sure any treated plants won't be damaged by its use.
Finally, when making your pesticide choice remember that most will only control certain stages of the development of the pest. Many only kill larvae, not the eggs. Others only kill the adults. Many fungicides are preventative and won't kill existing infections. Equally, some herbicides only kill germinated weeds but not established ones. The list goes on and only supports the instruction to read the label of any pesticide every time to make sure your selection is the best one for the job.
Before purchasing a pesticide learn all you can about the material, how to correctly use it and how to properly dispose of the empty container. Also, don't purchase the large bargain container. Only purchase the amount needed for the current job. Each time rethink any pesticide purchase and consider if a non-chemical option is the better bet.
We hope these last few week's articles on invertebrate pests, the beneficials, the IPM method and pesticides information and uses have helped you become educated, informed and empowered to feel more confident in your garden when it comes to exploring and choosing the best pest management, prevention options and solutions. Go forth and conquer.
Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.
Photo credits: UC Master Gardeners of Napa County, Wikimedia Commons (3rd image)
Information links:
IPM method:
http://ipm.ucanr.edu/QT/beneficialinsectscard.html
Pesticides
UC Pesticides in the Home and Landscape Information Home Page: http://ipm.ucanr.edu/GENERAL/pesticides_urban.html
Pesticides: Safe and Effective Use in the Home and Landscape:
http://ipm.ucanr.edu/PMG/PESTNOTES/pn74126.html
Active Ingredient Database: http://ipm.ucanr.edu/PMG/menu.pesticides.php
Some Organically Acceptable Pesticides Used in Gardens & Landscapes: http://ipm.ucanr.edu/PDF/MISC/Some_organic_pesticides_MG_handout.pdf
Less Toxic Insecticides http://ipm.ucanr.edu/PDF/QT/qtlesstoxicinsecticides.pdf
by Melody Kendall
Let's look at them, their chosen prey and how these wonderful natural enemies help to keep the garden pest populations in check.
Convergent lady beetle:
A favorite of children of all ages, this wonderful beetle is not only cute, but a very voracious hunter of soft-bodied insects, insect eggs with their special favorite prey being aphids. Lady beetles go through four stages of development: egg, larva, pupa and adult. Females can lay several hundred eggs in their growing-season lifespan of about two months.
Devastating to any aphid population the convergent lady beetle young larvae suck out the insides of the aphids while the older larvae and adults will chew and swallow the entire insect. Each adult lady beetle can consume about 100 aphids a day.
These convergent lady beetles can be purchased in stores or on-line but keep in mind that once they have cleared your area of aphids, they will fly off to find more hunting grounds. https://www2.ipm.ucanr.edu/natural-enemies/convergent-lady-beetle/
Green lacewing:
These pretty insects have trim ¾ inch long usually bright green bodies with golden eyes all topped off with the lacy wings that give them their name. Moving through four stages of development, the lacewings usually require 4-6 weeks to mature from egg to adult. The adults feed on honeydew, nectar and yeasts and some, but not all, are predaceous. The larvae are the hunters as they pierce their prey and suck out the insides. The green lacewing consume mites and soft-bodied insects like aphids, caterpillars, lace bugs, leafhoppers, mealybugs, psyllids, scales and thrips so, wow, quite the hungry predators. These too can be purchased as eggs or adults.
The adults are about ? -1 inch long with a mostly blackish or dark reddish hard shiny upper surface with prominent long legs and antennae. Predaceous ground beetles go through four stages of development that can take several months to more than a year depending on the food source and environment. Most take about a year to mature. When digging in the soil you might find the larvae which tend to lay straighter than the garden pests. Don't give the straight ones to the chickens. Hunting mostly during the night the adults are fast runners and rarely fly. During the day adults and larvae can be found in compost piles, leaf litter, mulch and under rocks, especially in moist locations. This is the long list of the predaceous ground beetle's prey: Caterpillars, root-feeding insects, soil-dwelling insects, and other ground-dwelling invertebrates including millipedes, slugs, and snails.
Depending on the species, the adult assassin bug is about ?-1/1/4 inches long and can be colors ranging from blackish, black and orange or a mix of all. They have long heads and bodies with long legs and narrow mouthparts. They can walk quickly when disturbed or when capturing prey and tend not to fly. Developing through three life stages the assassin bugs generally have one to two generations per season.
With their long needle-like mouthparts the assassin bugs feed on insects including caterpillars and larvae and nymphs of other true bugs. Impaling their victim with their tubular mouthparts, they inject venom and suck out the contents of the body. One species of assassin bug secretes a sticky substance to hold their prey in place. Being general predators they also feed on bees, lacewings, lady beetles and other beneficial species. Interestingly enough there is a species of assassin bugs that feeds on the blood of birds, mammals or reptiles.
Adult minute pirate bugs feature bulging eyes and an oblong oval somewhat flattened body. The 1/12 to ? inch long bug is colored mostly black, brown or purplish. Running through three stages of development that take about 3 weeks long during warm weather the pirate bugs can produce several generations in one year. Each growing season the predaceous minute pirate bugs are one of the first to begin feeding. Feeding through needle-like mouth parts both the larvae and adults suck the body fluids of their prey. Preferring spider mites and thrips they also feed on aphids, psyllids, small caterpillars, whiteflies and insect and mite eggs. They also feed on pollen and plant juices, but are not considered plant pests. Commercial greenhouses sometimes purchase and release the minute pirate bugs to control aphids in their greenhouses.
Dark brown to black with orange, red or yellow the adult soldier beetles have elongated bodies with bent down heads and segmented threadlike antennae. These adults are from 1/16 to 1 ? inches long, varying by species. Developing through 4 stages the adult soldier beetle lives a relatively short life and is mostly only observed in the spring through early summer months. The bulk of the soldier beetle's life cycle is as ground-dwelling larvae which can live 1-3 years. There are usually 1 or 2 generations of soldier beetles per year. The ground dwelling larvae are mainly predators of eggs, larvae and pupae of various arthropods, though some species feed on seeds and fleshy roots, but are not considered pests. Some species of adult soldier beetles feed on honeydew, nectar and pollen while others are predaceous, preying on aphids and other plant-sucking insects. The adults appear during the day and can be observed on leaves infested with aphids or other honeydew-secreting insects. The adult soldier beetle will drop from their perches like they are dead when disturbed. Their bright colors alert predators that they are distasteful as the larvae, pupae and adults alike excrete noxious, defensive chemicals from specialized abdominal glands.
https://www2.ipm.ucanr.edu/natural-enemies/soldier-beetles/
Spiders have a “yikes” factor, but consider spiders are beneficial because of all the pest insects they feed on. Spiders seen out in the open during the day are unlikely to bite and are just going about their business of pest patrol. The ones to worry about are usually hiding and not visible.
California has few dangerous spiders.
http://ipm.ucanr.edu/QT/commongardenspiderscard.html
Syrphids:
Adult syrphids or flower flies or hoverflies are slender flies ? to 1 inch long varying by species. The bodies of many of the adults are black with bands or strips of orange, yellow or white and resemble bees or wasps. Some species are brown, yellow, blue or a combination of all. Syrphids have four life cycles to maturity and the pupae require moisture and humidity to mature. Some species of Syrphids have five to seven generations per year while others have only one generation a year. In mild coastal climates they can be active all year. Most species of syrphid prey on aphids or mealybugs. Some feed on ants, caterpillars, froghoppers, psyllids, scales and other insects or mites. The larva can feed on upwards of 400 aphids before it pupates. 95% of syrphids are day active and are important pollinators. These adults are not predaceous as they consume honeydew, nectar, pollen and water.
Sixspotted thrips adults are about ? inch long with long hairlike fringes on their three dark spotted wings. These spots help distinguish this thrip from the other common California thrips species considered pests. The sixspotted thrips feeds on web spinning spider mites and other mites that don't spin webs. They feed on all stages of spider mites but prefer the immatures and do such a good job of clearing the spider mites out that few mites survive the feast.
https://www2.ipm.ucanr.edu/natural-enemies/sixspotted-thrips/
Parasitic wasps:
http://ipm.ucanr.edu/PMG/GARDEN/PLANTS/INVERT/wasp.html
These are the true heroes of the garden. Working diligently to reduce and control the invertebrate pest populations in our landscapes. To increase the effectiveness of resident natural enemies and any released natural enemies control the ant populations and reduce dust dispersal in your landscape. Grow flowering plants that provide nectar and pollen for adults and, most importantly, always research invertebrate pest control options. Use the right plant in the right place, declutter your garden and use barriers. Encourage natural predators in your gardens by avoiding the use of broad-spectrum pesticides. As a last resort, always research any pesticide before its use and find the least toxic pesticide that will do the job.
Next week we will wrap up this series with information on the IPM method of pest control and pesticides and their uses.
Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.
Information links: Natural Enemies and Biological Control
UC IPM Biological Control: http://ipm.ucanr.edu/PMG/menu.biocontrol.html
Biological Control and Natural Enemies of Invertebrates http://ipm.ucanr.edu/PMG/PESTNOTES/pn74140.html
Encouraging Beneficial Insects in Your Garden (Has a list of flowers that attract certain beneficials): pnw550.pdf (oregonstate.edu)
Attracting Beneficials to Your Garden: https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=16607
Natural Enemies in Your Garden: A Homeowner's Guide, a 63 page downloadable booklet from MSU:E-2719.layout (msu.edu)
Melody Kendall
There are legions of invertebrate garden pests that can wreak havoc in our gardens. They are the munchers, suckers, borers and slimers. In our area we mostly deal with a “dirty dozen” of invertebrate garden pests. This week we will present information on the remaining six: Snails and slugs, spider mites, thrips, white flies, earwigs and sow bugs/pill Bugs.
- Among the most despised garden pests they emerge from hiding at night and generally use their scraping mouths to munch their way through the garden by chewing holes in leaves and flowers of succulent garden plants and fruit.
- Snail and slugs are similar in structure and biology with the slugs lacking the external spiral shell.
- To view these pests at work you must observe them at night. Look for their signature ‘slime' trails during the daylight hours.
- To curtail infestations remove any hiding places like leaf debris, weedy areas, ivy and wood piles.
- Place your garden in the sunniest areas and keep clear of any sheltering plants or ground cover.
- Reduce moist surfaces by using drip irrigation systems
- When establishing the garden make sure it is mollusk free by surrounding it with a 4-6 inch copper band buried an inch below the ground and bent over. A similar band can be attached around the top edge of any raised beds.
- Consider snail-proof plants with stiff leaves and highly scented foliage
- Hand removal of snails and slugs is the best and easiest option.
- Pesticide baits will not work unless you remove their sheltering places in the landscape.
- Iron phosphate baits are safe for use around family and pets. Follow package instructions.
http://ipm.ucanr.edu/QT/snailsslugscard.html
- Tiny and difficult to see, these pests are common in fruit trees, vegetables, berries, vines and ornamental plants.
- Spider mites are arachnids just like spiders and ticks.
- They live mostly under the surfaces of leaves in dense colonies of possibly hundreds of mites.
- Heavy infestations feature dense webbing that can cover leaves, twigs and fruit.
- Spider mites are sucking insects. Damage first appears as a stippling of light dots in leaves and if heavily infested the leaves will turn yellow and fall off. Check the underside of leaves to view the tiny spider mites.
- Plants that are water stressed or experiencing hot dusty conditions are most susceptible.
- Spider mites have many natural enemies. These include predatory mites, thrips, lacewings, and minute pirate bugs
- To help curtail infestations of spider mites in your plants, keep dust down, plant ground covers, use mulches and irrigate regularly to avoid drought stress.
- Use a directed water spray on the undersides of the infested plant's leaves once a day to help remove spider mites.
- If you are sure the plants are infested a good choice would be to spray insecticidal oil and/or soap on the undersides of leaves. Only use this method if the plants are not drought stressed or the weather is not hot.
http://ipm.ucanr.edu/PMG/PESTNOTES/pn7405.html
- When thrips feed they distort or scar leaves, flowers or fruit. Healthy woody plants usually tolerate thrips though the damage can be unsightly. Fruits and vegetables can suffer more serious injuries.
- You will often notice the damage before seeing these tiny slender insects
- Look for scabby, silvery discolorations on fruit, leaves or petals, excrement on fruit or leaves and curled distorted or dead shoot tips and leaves.
- On a positive note, there are certain thrips that are beneficial predators of some insects and mites. More on those in next week's posting.
- Confirm thrips infestations before taking any action as harsh weather, poor plant care, pathogens and other invertebrates can cause similar damage.
- Shake the plant over white paper to see any dislodged thrips and hang sticky tape to capture flying thrips.
- Avoid overwatering and applying nitrogen fertilizer. Prune off any declining, injured or infested plant parts
- Use floating row covers and reflective mulches
- Use the least toxic method to conserve natural predators and parasites. If pesticides are used, wait until next season and spray new growth.
http://ipm.ucanr.edu/QT/thripscard.html
- Tiny sap-sucking insects: Adults fly around plants when disturbed and nymphs don't move, but cause most of the damage.
- Nymphs can be found on the undersides of leaves and secrete honeydew on leaves, fruit and under plants which then is covered with black sooty mold. Some species deposit a white wax on plants.
- Damage caused by the whitefly nymphs is yellowing, silvering or drying out of leaves.
- Inspect new plants for whiteflies before purchasing
- Prune any infested leaves when damage is detected and hose off adults with a strong stream of water.
- Promptly destroy any infected plants. Do not put in compost.
- Use of sticky traps, insecticidal soaps or oils and reflective mulch are deterrents.
- Avoid use of pesticides to protect the natural enemies populations.
http://ipm.ucanr.edu/PMG/PESTNOTES/pn7401.html
- Fierce looking, but not harmful to humans.
- Feed at night on seedling vegetables and chew holes in annual flowers, soft fruit and corn silks.
- Also considered beneficial because they also feed on aphids and other insects.
- Earwigs hide during the day in dark, cool, moist places in the landscape. They also hide in vegetables and flowers.
- Best control method is to remove hiding places and moist areas.
- Start a trapping program to have the best result. Continue to trap earwigs until traps are empty.
- Use drip irrigation when possible and use sticky substances as Tanglefoot around trunks of fruit trees.
- Insecticides should rarely be needed.
http://ipm.ucanr.edu/PMG/PESTNOTES/pn74102.html
- Sow bugs and pill bugs are not actually insects or true bugs, but soil-dwelling crustaceans.
- Feed mostly on decaying plant material. They can also chew on fruit, succulent plant parts, seedling and vegetables that touch damp soil.
- When disturbed the pill bugs commonly curl into a ball thus the nickname ‘rolly polly'. The Sowbugs cannot roll so they just normally scurry away when exposed.
- Adults of both can live from 2 to 5 years.
- Since their favored food source is decaying plant material, they are important decomposers but they are somewhat indiscriminate. When confronted by succulent plant material resting on the soil, they often chow down making them a nuisance.
- To control sowbugs and pill bugs reduce decaying moist organic matter in the garden.
- Use irrigation to support healthy plants, but not increasing sustained moist areas. Water early in the day to allow excess moisture to evaporate.
- Keep compost and mulch away from the base of plants and building foundations
- Start a trapping program to have the best result. Continue to trap the pill bugs and sow bugs until the traps are empty.
http://ipm.ucanr.edu/PMG/PESTNOTES/pn74102.html
This concludes the dirty dozen postings. We have discussed twelve common invertebrate pests in our area: aphids, ants, cabbage worms, grubs, scale insects, snails & slugs, spider mites, thrips, whiteflies, earwigs and sow bugs and pill bugs. Armed with this information we hope that you now can identify these pests and begin your management program.
Help is on the way! Our next posting will talk about all the wonderful natural enemies mother nature has provided to help curtail this dirty dozen: the convergent lady beetle, green lacewing, predaceous ground beetle, assassin bug, pirate bug, soldier beetle, spider, syrphid fly, six-spotted thrips and predatory (parasitic) wasps.
Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.
Photo credits: Jack Kelly Clark, University of New Hampshire
Information Links:
UC Home Site for information on managing pests in the home, garden, turf and landscape: http://ipm.ucanr.edu/PMG/menu.homegarden.html
Pest Notes Library http://ipm.ucanr.edu/PMG/PESTNOTES/index.html
Plant Disease information: UC IPM Plant diseases http://ipm.ucanr.edu/PMG/diseases/diseaseslist.html
How to manage pests http://ipm.ucanr.edu/TOOLS/TURF/PESTS/innem.html
by Melody Kendall
This is the first post of several devoted to discussing garden pests, natural enemies, physical controls and finally pesticide information and uses. There are legions of invertebrate garden pests in the world that can wreak havoc in our landscapes. The garden pest culprits are all those pesky munchers, suckers, borers and slimers. Fortunately, in our area we mostly deal with a ‘dirty dozen' of invertebrate garden pests. This week we will present information on the first six of that "dirty dozen": Aphids, Ants, Imported Cabbage Worms, Codling Moths, Grubs and Scale Insects.
• Almost all plants have some aphid species that will sometimes feed on it.
• They prefer lush new growth so avoid over-fertilizing your plants
• Aphids are actually herbivores. They feed by sucking the plant juices out of the leaves and stems of plants frequently causing the leaves to curl. Interestingly, the juices the aphids drink often have more sugar than protein. So, to access the protein, the aphids drink more of the sugary juices than they need. Because of this they excrete a lot of the excess sugar causing sticky "honeydew." Ants like to drink honeydew and will actually manage populations of aphids by protecting them from predators.
• Low to moderate numbers usually don't damage gardens or landscape trees.
• Aphids can usually just be washed off with a firm stream of water. When pesticides are warranted use the less-toxic products like insecticidal soaps and oils.
• Often removing any ants from the situation will cause the aphid population to decline.
• If aphid numbers are high natural enemies often feed on them.
http://ipm.ucanr.edu/QT/aphidscard.html
• There are more than 10,000 species of ants in the world.
• Actually ants in the garden are not always a bad thing. They can improve pollination rates when moving from flower to flower in search of food. Ants often help control pests by eating their eggs and young or disturbing them during feeding. When digging their tunnels the ants aerate the soil and help to decompose organic material to fertilize the plants.
• On the down side, ants will protect and increase the numbers of the 'honeydew' producing pests in the garden. Manage ants by removing the 'honeydew' producing insects. Try wrapping a sticky material around the base of affected trees and shrubs to prevent ant access. Ask your nursery about these products.
• Keep leaf litter, mulch, irrigation and foliage away from foundations of buildings where ants are not wanted.
• Use less-toxic pesticide if needed
http://ipm.ucanr.edu/PMG/GARDEN/CONTROLS/antmanagement.html
• Native to eastern Europe
• The white adult cabbage butterflies lay eggs singly on leaves and the resulting green, hairy faintly yellow/orange striped larvae grow as they eat your brassica plants and can be up to one inch long. Though slow, the greedy larvae feed on both the inner and outer leaves, often along the rib, leaving fecal pellets behind.
• The cabbageworm is active all year here California.
• Floating row covers can work to help deter the butterflies from laying their eggs.
• Hand picking the larvae, while not for the is very satisfying while you teach them to fly (hopefully not into the neighbor's yard) and/or feed them to the chickens.
• Bacillus thuringiensis or spinosad organic pesticides are very effective.
http://ipm.ucanr.edu/PMG/GARDEN/VEGES/PESTS/importcabwrm.html
• In California two to four generations can occur per year. Adult moths lay their eggs on fruit and leaves. Hatching larvae immediately bore into fruit leaving a reddish brown trail of frass. Look for reddish brown points of frass on the fruit and removed affected fruit immediately.
• After the larvae overwinter in leaf debris or under the bark of apples, pears or walnuts trees, they pupate in mid-March to April. Destroy raked up fruit that has dropped from the tree.
• Bagging the ½-1 inch fruit four-six weeks after bloom can help curtail the Codling Moth
• Combining the use of low toxic pesticides with non chemical methods is the most sound environmental approach for control. For severe infestations use Cyd-X or spinosad before trying more toxic pesticides. Precisely timed pesticide applications are needed to affect the larvae.
• Early fruiting varieties are less likely to suffer damage from the Codling Moth
http://ipm.ucanr.edu/QT/codlingmothcard.html
• Grubs are root feeders, and are typically found in lawns but can also be found in garden beds. Grubs found in garden beds are most likely the larval stage of masked chafer beetles. Be careful when amending your beds with home prepared compost as it might contain masked chafer eggs. Before applying compost, be sure it has been properly prepared with sufficient heat to decompose the organic material and to kill insect eggs and other organisms. Hand removal of grubs is easy, and if you have chickens or know someone who does, pass them along. You'll make a friend for life.
• Tiphiid wasps larvae are common parasites of masked chafer beetles, but may not provide effective control.
• Beneficial nematodes can also be used for biological control of grubs.
• As a last resort, neonicotinoid insecticides like imidacloprid can help. Proper timing is essential.
https://www2.ipm.ucanr.edu/agriculture/turfgrass/Masked-Chafers-White-Grubs/
• Young scales are small, slow moving crawlers with legs that drop off when they mature into the immobile adults. Some adult scale appear as elongated circular discolorations resembling raised bark. No obvious head or legs are visible. They are sucking insects that can cause yellowing or dropping of leaves on trees, shrubs and houseplants. Sticky honeydew and sooty mold growing on the honeydew can be the result of a severe soft scale infestation. Control any resident ant access to affected plants. They like the honeydew and will protect the scales from any natural enemies.
• Armored scales are tiny and flat and are usually easy to remove. They do not secrete honeydew.
• Most scales are plant specific. It's up to the gardener whether or not to remove plants that are prone to scale infestations.
• Encourage natural enemies populations
• Applications of horticultural oil during dormant season and when crawlers are active might help to reduce scale numbers
http://ipm.ucanr.edu/PMG/PESTNOTES/pn7408.html
Next week we will finish up our list of the ‘dirty dozen' of invertebrate pests that are all common in our area: snails and slugs, spider mites, thrips, white flies, earwigs, sow bugs and pill bugs. Meanwhile, keep your eyes peeled in your landscape for any of these culprits and take the appropriate action.
Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.
Photo credits: Jack Kelly Clark
Information Links:
UC Home Site for information on managing pests in the home, garden, turf and landscape: http://ipm.ucanr.edu/PMG/menu.homegarden.html
Pest Notes Library http://ipm.ucanr.edu/PMG/PESTNOTES/index.html
Plant Disease information: UC IPM
Plant diseases: http://ipm.ucanr.edu/PMG/diseases/diseaseslist.html
How to manage pests: http://ipm.ucanr.edu/TOOLS/TURF/PESTS/innem.html