UC Master Gardeners, Santa Clara County, CA
University of California
UC Master Gardeners, Santa Clara County, CA

April Tips

Monthly tips are categorized by To-Dos, What to Plant, or Pests and Diseases. Scroll through the list to see items in each category. Also, refer to our list of tips useful for any month.

1. To-do

  • Irrigation and Graywater -

    As temperatures rise, irrigation becomes more important. Container plants will begin to dry out and need to be checked every few days. Inspect irrigation systems for leaks, clogged drip emitters, misaligned sprinkler heads, and other problems which could waste water. Make sure the water is going to the root zones of the plants.

    Things to consider:

    Use a smart irrigation controller. These help adjust watering based on local conditions. Learn more about smart controllers.

    Collect water from the shower as it heats up and use it to water any plants.

    Use graywater from garage sinks and washing machines to water ornamentals and lawns. UC has a publication titled Use of Graywater in Urban Landscapes in California.

    - March, April, May, June, July, August
  • Remove Thatch in Lawns -

    If you have a lawn, April is the time to remove thatch. Thatch is a layer of dead and living stems, roots, stolons, and rhizomes, between the green blades of grass and the soil surface. If thatch becomes too thick, it can keep water, air, and nutrients from reaching the soil and roots. Thatch can be removed with a thatch rake to improve the health of the grass. The UC Guide to Healthy Lawns has more information.

    If you are tired of mowing and raking and watering that lawn, you may want to check on the Santa Clara Valley Water District's Landscape Rebate Program. Even if the funding is used up for the year, you can still replace your lawn to conserve water, time, and energy. But don't start by digging it up. Instead, sheet mulch the area. Then you can add drought-resistant native plants or ground cover, such as yarrow, thyme, sage, creeping manzanita or ceanothus.

    - April
  • Pruning Dead Branches -

    As dormant trees and shrubs begin to leaf out, it will be fairly easy to see which parts are dead. Prune back to live wood to avoid diseases and keep your garden healthy. Swelling buds and a thin green layer just under the bark are signs that the wood is alive. Find tips on pruning at the UC Home Orchard website. If larger trees need pruning, hire a professional. The International Society of Arboriculture (ISA) has a searchable list of certified arborists.

    - March, April
  • Pruning Azaleas and Rhododendrons -

    Azaleas and rhododendrons can be pruned as soon as they finish flowering. This is also a good time to fertilize them. Choose an acid-forming fertilizer blended for these particular plants, and be sure to follow the label directions for amounts. Learn more by visiting the Azalea and Rhododendron society websites.

    - April, May
  • Navel Orange Harvesting -

    If you have Navel orange trees, the crop will be ripening. Oranges left on the tree too long will dry out and become inedible or get eaten by rats. Instead, harvest the entire crop by the end of April and use the bounty to make marmalade, chutney and spiced oranges.

    QUARANTINE WARNING: Most of Santa Clara County is under quarantine for citrus due to the asian citrus psyllid and huanglongbing disease. Check the Santa Clara County Quarantine Map to see if you're affected and review our asian citrus psyllid page for what can and can't be moved across quarantine boundaries.

    - February, March, April
  • Pruning Bougainvillea -

    You can prune at any time to shape or direct growth. If it is growing on a wall, cut back long stems to keep producing flowering wood. Hard pruning to renew the plant should be done in the spring after the last frost.

    - April, Any month
  • Drip Irrigation -

    Low volume drip irrigation systemConsider various forms of irrigation conversion! Irrigation systems, especially drip and micro-sprinklers, have drastically improved over the last few years. For example, there are kits that convert pop-up sprinkler heads to low-flow systems. The conversion kits include a pressure regulator to control changes in pressure and a filter to improve water quality. Water usage is reduced through better water management, control of distribution and less loss from evaporation. Other advantages include :

    - Water is placed more accurately and efficiently in the root zone, it is applied at a slow rate that reduces loss from runoff.
    - Dry soil between plants allows you to work in the garden between irrigating.

    The key to success is watering long enough to supply adequate water to the root zone. Inappropriate watering commonly damages landscape plants. As with any irrigation system, they are efficient only when soil around the plants being irrigated is regularly monitored for proper moisture levels (Reference: UC Pest Note Poor Water Management, Poor Drainage).

    - April, May, June, July, August, September, Any month
  • Tomato Staking -

    It's time to start planning how you will stake your tomatoes. You will want to stake your tomatoes right after you plant your seedlings. Here are the various Tomato Staking Techniques we have tried.

    - April, May, June
  • Soil Management - Compost vs Mulch -

    Many home gardeners are confused about the terms “compost” and “mulch;” frequently these terms are used interchangeably, but they are not really the same thing. Here is a Comparison of Soil and Mulch from UCCE.

    Amend soil with compost to create soil that will retain water but still drain well enough for roots to have the air and water they need.

    Benefits of compost
    - Forms aggregate particles with clay
    - Creates larger pore spaces for water & air
    - Helps release nutrients from clay so that plant roots can absorb them
    - Supports the soil foodweb by providing nutrients for the organisms
    - Lowers pH somewhat.

    Benefits of mulch
    Mulch does not get worked into the soil. It sits on top of your irrigation system and helps:

    - Control weeds
    - Prevent erosion
    - Preserve soil moisture
    - Keep roots cool and moist

    - March, April, May, Any month
  • Pruning Camelias -

    April and May are the best time to prune camellia. Camellia should be pruned just after flowering and before new vegetative growth gets going. If you prune later in the season, you risk damaging next years blossoms.

    - April, May
  • Growing Vegetables in Containers -

    Growing Vegetables in ContainersContainer grown vegetables can be decorative as well as good to eat. Almost any vegetable can be grown in a container if given the proper care. Eggplant, peppers, tomatoes, lettuce, onions, carrots, cucumbers and herbs do well. Use our Vegetable Planting Chart to decide when to plant.

    One of the biggest problems is that containers dry out very fast and nutrients wash away. Both are solvable. Do not use clay pots, which dry out quickly. Plastic, composite or wooden half-barrels are good, but avoid dark colors that can absorb heat. Vegetables like a roomy container.

    There must be drainage holes in the bottom but it is not recommended that you put pebbles or broken crockery in the bottom. Use a good commercial potting mix, not planter or planting mix. Group the containers together so they will shade one another.

    The hot summer sun can heat the soil to unhealthy levels. Water whenever the soil is dry. You can test by digging your fingers into the dirt. You may have to water more than once a day. A simple drip system is easy to install and will make your container garden almost foolproof. Fertilize every week with a water-soluble fertilizer.

    - February, March, April, October, November
  • Poison Oak -

    Poison oak is a California native plant that provides shelter and food for many native birds and other creatures. The downside is that at least 75% of us develop allergic contact dermatitis to the plant. Unwanted poison oak can be pulled or dug up by allergy-resistant friends, remove plants in early spring or late fall when the soil is moist and it is easier to dislodge rootstocks.

    A complete list of management options, including herbicide control, is contained in the UC Pest Note on Poison Oak. Under no circumstances should poison oak be burned.

    - February, March, April, November
  • Protecting Birds and Crops -

    This is nesting season for many birds, so be sure to check for active nests before pruning trees. Birds are good for natural pest control, as they eat many insects, and they improve your garden’s biodiversity. You can also encourage birds in your yard by providing food and water for them. Just be sure the water stays fresh and clean.

    To protect fruit and nut trees from marauding birds, PVC structures covered with netting can save your crop. If netting is placed directly on the tree, birds will still be able to reach much of the fruit. There's more information in the UC Pest Note on Birds on Tree Fruits and Vines.

    - April
  • Weed Management -
    While some weeds are edible (purslane, nettles, dandelions), many are a nuisance and compete with your chosen plants for water and nutrients.
     
    Whichever variation of “One year’s seeds makes seven years’ weeds” you prefer, the truth remains: a key part of weed control is not letting them go to seed. For best results, work on removing weeds before they are able to propagate. Hand pulling and hoeing are effective methods for killing many common weeds.
     
    Knowing what kind of weeds you have can be helpful in choosing the best management method. If you want to know what a weed is called or how it propagates, check into online resources or UC's Weed Gallery. If they propagate by seed, pull or hoe them before they flower and go to seed. If they re-grow from roots, pull up as much of the root as possible. Many weeds, like Bermuda grass, have multiple ways of multiplying. Only non-propagating parts are advisable to throw in the compost bin.
     
     
    - February, March, April, May, June, July, August, Any month
  • Hardening Off Seedlings -

    Seedlings that have been raised in protected conditions, like in greenhouses or indoors, need to be gradually exposed to outdoor conditions for one to two weeks before transplanting. This process is known as “hardening off.”

    To harden off seedlings, first move them outside to a shady, wind-sheltered area for a few hours a day, bringing them inside at night. After a few days of that treatment, place them in the sun for a few hours in the morning or late afternoon and gradually increase the sun exposure. Reduce the frequency of watering, but do not allow the plants to wilt. Do not place seedlings outside on really windy days or when the temperatures are below 45 deg F.

    After a couple of weeks, once the seedlings are used to full sun and can stay outside overnight, they are hardened off and are ready to transplant into the garden.

    - April, May
  • Pruning Roses to Minimize Disease -

    A chemical-free way to keep roses healthy and minimize disease associated with foggy summer mornings is to prune to improve air circulation.

    Roses pruning photo from University of Illinois
    Make sure you wear gloves to protect your hands from thorns and use clean, sharp tools. First, remove dead and diseased parts. Then remove anything that is growing where it doesn’t belong. This includes suckers below the graft union and branches that are crossing or growing towards the middle of the plant. Finally, prune for shape and health. Cut back to about four or five evenly-spaced strong canes, leaving a few buds on each cane. Make pruning cuts ¼ inch above outward-facing buds in order to create a vase shape that allows for good air circulation. Good air circulation allows the morning dew to dry and helps prevent rust and powdery mildew. 

    More Information: Rose Pruning

    - January, February, March, April, December
  • Fruit Tree Sunburn Protection -

    In hot, sunny weather, the bark of fruit trees, especially when they're young, can get sunburned and begin to crack or peel. This allows tree borers and other pests and diseases to enter, which can cause significant damage to the trees. To protect exposed trees, the bark can be painted with white latex paint, mixed 50-50 with water.

    If you have a new fruit tree that hasn't been painted, do it now. And consider other fruit tree trunks if they have significant sun exposure.

    - April, May
  • Container Color Choice -

    If you are growing plants in containers, keep in mind that light colors do a better job at reflecting the sun. This helps keep the soil from drying out too quickly and reduces the chances of the roots burning. If you already have dark pots, consider painting them a lighter color, or be especially careful about watering.

    - April, May, June, July
  • Raised Beds -
    Raised beds make gardening easier in several ways. You don’t have to bend over as far to reach the surface. You can add any soil blend you like and you won’t compact the soil around the roots by walking on it. You can also better protect the roots and plants from critters. You can build them with wood or cinder blocks or anything that doesn’t have chemicals that can leach out into your food, for example, no pressure-treated lumber or railroad ties with creosote. If you’re using wood, redwood and cedar are the most resistant to pests and rot. You can be particularly green by using old fence boards or decking. Locate the beds where the plants will get the sun they need. Make sure the width is not more than twice your arm length so that you can easily reach all parts from the sides. To prevent gophers and other pests from tunneling into the root area, line the bottom of the bed with hardware cloth.
     
     
    - March, April

2. What to plant

  • Herbs -
    Many herbs can be grown both indoors and out, in pots or in the ground. Rosemary grows large and needs to be in the ground or a big pot. If you use basil to make pesto, you may want a row of it in the garden. Yet most herbs tend to be used in small quantities for seasoning and so they can be grown in small containers. They can be on the kitchen counter or a windowsill for ease of use in cooking. They can be on a patio if you are in an apartment or condo. And they are well suited to container gardening outdoors. Woody herbs can be grown from cuttings, lemongrass can be started from stalks from the store, and most others can be started from seed. After harvesting, many can be dried as well as used fresh.
     
    More Information: Growing Herbs
     
    - March, April, May, September, October
  • High Yield Vegetables -
    There are many considerations for choosing which edibles to plant in your garden. A particularly important one this year may be high yield. The more the plants produce, the more food you will have right on your property. Zucchini naturally comes to mind first. You may need to research additional recipes, and your neighbors may be more amenable this summer to having bags of zucchini dropped on their doorsteps during the night. Other plants that produce a lot are tomatoes and eggplant. Green beans need to be picked almost daily so they will give you an ongoing source of vegetables for a couple of months. Certain cucumbers like Persian cucumbers are eaten small and produce prolifically, enabling you to eat cucumbers more often than if you were waiting for full-size varieties. Vining plants, e.g., melons, will give you more to eat if grown on vertical supports rather than having the produce lie on the ground where it can be more readily eaten by pests.
     
    More Information: Home Garden Productivity
     
    - April, May, June
  • Seed Viability -
    Seed packets have a “packed for” date on the back. Yet seeds can still be viable for years beyond that date if stored correctly. Ideal storage conditions are cool and dry. The older the seeds are, the lower the germination rate will be. So plant more of the older seeds than the number of plants you ultimately want. You can do a germination test by putting seeds on a damp paper towel and enclosing them in plastic to keep them uniformly moist. Do this right before planting time so you can transplant the ones that successfully germinate. Or you can take your chances and just plant them directly and see what comes up. If you are saving your own seeds, make sure to choose seeds from the healthiest plants.
     
    Whenever it's hard to find flower seedlings, if you have some old flower seed packets, you can scatter the seeds randomly in a section of your yard and enjoy whatever flowers.
     
    More Information: Vegetable Seed Viability
     
    - January, February, March, April, May, August, September, October
  • Chrysanthemums -
    This is a less common but good time to plant chrysanthemums. They will have plenty of time to develop a good root system before the cold winter and are more likely to bloom perennially in your garden than if they are started in the fall. You can also start chrysanthemums from cuttings. Plant them in amended, well-drained soil, or grow them in a large container. Keep them moist but not wet. They do well in full sunshine, yet a little afternoon shade is fine in hot areas. If you pinch the growing tips as they grow, they will branch and be bushier. Otherwise, be prepared to provide support if they grow tall. Also, pinching off some of the buds will result in fewer yet much larger blooms. There is a Bay Area Chrysanthemum Society for local information and sharing.       
     
     
    - April, May, June, July
  • Thyme -
    Thyme is much more than an herb to season food. In ancient times it was brewed by Egyptians for mummification, bathed in by Greek soldiers for courage in battle, and used by the Sumerians as an antiseptic and antifungal. And if you want a real surprise, check out the active ingredient list on a bottle of Listerine mouthwash. In your own garden it can be used for culinary purposes or as a purely ornamental landscape feature. It grows best in well-drained soil and sunshine, although it will tolerate some shade. It is quite drought tolerant once established. Common/garden thyme (Thymus vulgaris) is an excellent all-purpose thyme, growing to a foot tall and up to two feet wide. Lemon thyme (Thymus citriodorus), with its lemon scent, makes a nice evergreen border. Creeping thyme (Thymus serpyllum) stays short and can be used as a ground cover or between stepping stones. Thyme is attractive to butterflies and bees. 
     
    More Information: Growing and Using Thyme
     
    - March, April, May, June, July
  • Growing Purple Carrots -

    If you only buy carrots at the supermarket, you may think that they are all orange. It is believed that carrots were originally purple, with orange becoming popular through Dutch breeding. Several colors are now available at Farmers’ Markets and by growing your own. Springtime is a good time to start carrots from seed. Transplanting is not advised because you can easily damage the roots which are the relevant plant part.  Loose soil is important so that the carrots will grow straight. Scatter the seeds over the soil with as thin a covering as possible, keep moist until germination, and harvest when the tops expand to a good size. The Master Gardeners have done germination and growing experiments with different varieties and soil blends. Covering seeds with a thin layer of vermiculite yielded the fastest and highest rate of germination. Carrots are slow to germinate and could take as long as 3 weeks. Thin to 2 or 3 inches apart. For growing, a soil blend of 1/3 compost and 2/3 soil produced higher-weight carrots than blends with half of the soil replaced with either sand or perlite.

    Some common problems are twisted roots from planting too close together, forked or deformed roots from clods and rocks in the soil, a hairy root from too much nitrogen and splitting from too much water.

    More Information: Growing Carrots

    - February, March, April, September
  • Easter Lilies -
    Beautiful white Easter lilies are normally everywhere this time of year – in nurseries, on Easter dinner tables, and in churches. How do they all come into bloom every year just in time for the moveable Easter holiday? The blooms are forced in commercial growing operations with greenhouses carefully controlled for temperature, light, and moisture. 95% of the bulbs are started in ten farms along the California-Oregon border. The plants are native to Taiwan and Japan and were first described in a Japanese gardening book in 1681. You can plant them outdoors after Easter in moist, well-drained soil with partial sun. Their natural cycle will lead to blooms closer to June in subsequent years. Just don’t let your cats eat them!
     
    More Information: Easter Lily diseases 
     
    - April
  • Bare-Root Fruit and Nut Trees, Berries and Grapes -

    March or April is an excellent time to add bare root fruit and nut trees, grape vines, and bramble fruits to the landscape. These perennial edibles can provide decades of food production with a minimal investment of time and money. For more detailed information on specific varieties, take a look at the UC Backyard Orchard website.

    - March, April
  • Don't Plant an Invasive Plant -

    According to PlantRight, so-called invasive plants "escape into open landscapes and cause a variety of ecological problems. They displace native plants and wildlife, increase wildfire and flood danger, clog valuable waterways, degrade recreational opportunities, and destroy productive range and timberlands."

    PlantRight has identified the following as invasive in Northern California: Green fountain grass (Pennisetum setaceum), Periwinkle (Vinca major), Pampas grass (Cortaderia selloana), Highway iceplant (Carpobrotus edulis), Mexican feathergrass (Stipa / Nassella tenuissima), Yellow Flag Iris (Iris pseudacrorus), Water Hyacinth (Eichhornia crassipes).

    With just a little research you can avoid using plants that are unfriendly to the Bay Area. 
     
    - April, May, June, July, August, September
  • Attracting Bees -

    Bees are pollination workhorses, increasing garden production. Many plants will not produce fruit unless flowers are pollinated. Colorful annuals, such as Cosmos, edible African Blue Basil, and Salvias attract bees. You can also allow herbs and other plants to flower to create bee-friendly landscapes.

    The University of California at Davis has a garden dedicated to bees. The Honey Bee Haven website has more resources, including a list of plants they grow.

    - March, April, May, June, September, October
  • When to Plant Cool-season Vegetables -

    In Santa Clara County, cool-season vegetables such as beets, Cool season leafy vegetablesradishes, peas, arugula, bok choy, chard, collard, lettuce, mustard greens, broccoli, cabbage, and spinach, can be planted in very early spring for early summer and harvested before they bolt (go to seed), or in late summer for harvest in winter. Use our Vegetable Planting Chart as a planting guideline.

    Cool-season vegetables grow well in temperatures ranging from 55°F to 75°F. Take a good look at your garden to determine the best areas for planting, remembering that cool-season vegetables need 6-8 hours daily of sun. 

     

    - February, March, April, September, October
  • Plants to Attract Butterflies -

    Butterfly populations fluctuate in response to climate and habitat conditions. Many have specific host plants on which they feed and breed. Some common plants for attracting butterflies are milkweed, lantana, buddleia, and zinnias. For an extensive list of relationships between specific butterflies and host plants, see Art Shapiro's Butterfly Site at UC Davis.

    - March, April, May, June
  • Starting Warm-Season Vegetables -

    Starting your own seedlings is fun, easy and can please your taste buds, too! You can select vegetables that are grown for a particular flavor such as heirloom varieties, many of which are not offered in garden centers. You can successfully start some vegetables (tomatoes, peppers, eggplants) from seed for transplanting this summer season. If seed starting isn’t for you or it is too late for you to start with seeds, consider buying transplants from our Spring Garden Market in April.

    There are two ways to start your seeds: direct sow straight into your garden or indoor sow. Direct sowing is easy for some plants such as peas and beets—see our Vegetable Planting Chart for more vegetables suitable for direct sowing now. Tomatoes, eggplants, and peppers are best started indoors and then planted in the ground after they are developed and sturdy. New plants and seedlings started indoors need to be hardened off. See Hardening off Seedlings before you plant them in the ground.

    Three factors influence germination: water, temperature, and light. Information found on the seed packages will show which conditions are best for germination. Peppers in particular germinate best with high soil temperature. Using a heating pad is one way that this can be done indoors.

    When reusing pots for seed starting, prevent the spread of plant diseases by making sure they are clean. Remove any remaining soil and cobwebs; then clean with a 10% bleach solution: 1 part bleach to 9 parts water.

    If you started seeds earlier in the year and they're outgrowing their pots, March may be a good time to move them into larger pots. Don’t try to plant them outdoors until after the soil reaches 65°F for healthy growth (and nighttime temperatures over 55°F). The soil temperatures outside are still too cold in March for planting summer vegetables in the ground.

    When transplanting, be sure to read packet directions for planting depth, spacing, and sun requirements for the best results.

    - February, March, April
  • Asian Vegetables -
    You can easily grow some vegetables used in different types of Asian cuisine and found in Asian markets. They are not necessarily native to Asia but have found their way into various cuisines. One way to decide which food to grow yourself is to choose varieties that aren't readily available or are more expensive in your local markets. It’s also fun to impress your family, friends, and neighbors with something they may not have seen growing before. Possibilities include sesame seeds, bitter melon, daikon radishes, gai choy, and opo. You can start cruciferous vegetables such as bok choy and Napa cabbage from seed now.
     
    More Information: Asian Vegetable Varieties
     
    - February, March, April, May, June, September, October
  • "Arboretum All-Stars" -

    Arboretum All Stars logoThis is the best tool for landscape planning available to Northern California gardeners! The UC Davis Arboretum All-Stars are plants found to be especially successful in California. The website covers essential planting basics for landscape planning, including easy-to-grow plants with low-water needs, fewer pest problems, and other outstanding qualities. As an added bonus, most are California natives that attract beneficial wildlife.

    - April, October, Any month

3. Pests and Diseases

  • Aphids on Seedlings -

    If you have plants started in greenhouses, be sure to check for aphids. These tiny pests can suck the life from small plants and spread to their neighbors. Look at the underside of leaves, especially on tender new growth. Aphids can be wiped off leaves, or you can dunk seedlings in a bucket of water. See UC Pest Note on Aphids for more information.

    - April
  • Snails and Slugs -

    Snails and slugs are patrolling your garden right now looking for new growth. Our preferred non-toxic method for dealing with them is to handpick early in the morning, or at night by flashlight. They can be saved for your friends with chickens, or crushed in place. If you do use snail bait, those made with iron phosphate are not toxic to pets and wildlife and they work well enough. For a full run-down of which management methods work, see the UC Pest Note on Snails and Slugs.

    - February, March, April, June, October
  • Rats -

    Have you found snail empty shells stashed in out of the way places, hollowed out Navel oranges, Meyer lemons with no skins, tomatoes with bite marks, fruit with holes gnawed in them or grape skins or cherry tomato skins scattered around? This could indicate the presence of rats. The UC IPM Pest Note on Rats provides a wealth of scientific information.

    Rats show up when your citrus, tomato or fruit first start to ripen. Rats are agile climbers and usually live and nest in shrubs, trees, and dense ground cover like ivy. Good sanitation is required. Garbage and garden debris should be eliminated. Use tight fitting lids on garbage cans. Thin out dense vegetation to make the habitat less desirable. Mow ivy once a year to the ground. Climbing ivies on fences or buildings should be removed.

    Trapping is the safest and easiest method for controlling rats. The simple snap trap is effective. The most important thing about trapping rats is to have lots of patience and keep trying. Wet some oatmeal enough for it to hold together, add dog or cat kibble or bits of lightly cooked bacon mixed in. Tie a walnut to the trigger and add a dab of peanut butter.

    Other baits to try are peanut butter and fresh fruit, but try to have something tied to the trigger. Set traps where rats are likely to travel or where you see droppings along fence lines or buildings. Bait the trap but do not set it for several days. Try different baits in multiple traps until you find one the rats like. Put two traps facing each other. After the rats are accustomed to being fed, then set the traps. If the rat springs the trap but doesn't get caught, move the traps to a different place and change to different baits. Rats prefer secluded spots and will be less wary there. Be sure to secure the trap with a wire or nails. Above all be patient and use multiple traps.

    - March, April, July, August, September, Any month
  • Citrus Sooty Leaves -

    Sooty mold on citrus may be a byproduct of sucking insects such as aphid, mealy bug, soft scale or whitefly. Ants will protect these pests against predators in exchange for the honeydew that the pests produce. The sooty mold grows on the honeydew. Try washing off the sucking insects with a strong water stream. The next step is control of the ants. Ants may be managed by applying a sticky compound around the trunk and trimming limbs touching buildings or other access points. Baits at the base of the tree also help. For more information about specific controls, see the UC Pest Note on Sooty Mold.

    - April
  • Termites -

    TermitesTermites are very common in Santa Clara Valley.  The first sign of infestation may be the presence of winged forms or fecal pellets pushed out of the infested wood. 

    See the UC Pest Note on Termites to identify which type is present and the methods of control. Learn all you can before calling in the professionals.

    - April, November
  • Brown Marmorated Stink Bug -

    Native to Eastern Asia, this pest was introduced to the United States in the 1990s and has been established in Santa Clara County. Some features to distinguish these bugs from other stink bugs are white stripes on the antennae, a blunt head shape, and smooth shoulder margins.

    They feed and reproduce on a variety of plants and are particularly damaging to fruit. You can cut cosmetic damage off fruit and still eat the rest of the fruit. To keep out stink bugs, cover vegetable plants with row covers. You can pick the bugs off plants and squish them or knock them off into soapy water. They are attracted to light and can get into homes where if vacuumed up, they can stink up your vacuum bag.

     
    - March, April, May, June, July, August, September
  • Avocados, Brown Spot -

    The brown patch that looks like a turtle's back is called Carapace Spot. It is corky and usually cracked into angular divisions. It is caused by rubbing or brushing of tender young fruit on leaves or stems in the wind, but the fruit is usually undamaged under the spot. Just cut out the spot. More pictures of avocado problems can be found on UC Pest Note On Causes of Avocado Fruit Damage.

    - April
  • Citrus Leaf Drop & Yellowing -

    Leaf drop from citrus trees is normal. Washington Navel oranges may lose over 3,000 leaves a day during peak leaf drop in the spring. Valencia oranges may lose about 1500 a day. Problems that can cause excessive leaf drop beyond these numbers are lack of water and a heavy infestation of spider mites. The tree's leaves will have brown spots if affected by the mites. You can wash them off with a strong water spray. Bud and small fruit drop is also normal. For further information see UC Pest Note on Diseases and Disorders of Citrus Leaves and Twigs.

    - April
  • Oakworm -

    This is a pest of California Live Oaks. The adult oakworm moth is tan-to-gray colored with a wing span of about an inch. It lays white eggs twice a year that turn reddish or brown before hatching. The first hatch is in November and overwinters on the leaves, growing and eating more as the weather warms. At full size, the larva is about an inch long with a yellowish green body, dark stripes down the side and large brown head. Outbreaks occur every eight to ten years in the Bay Area. In late March or April, look for little green pellets (droppings) falling from oak trees. A second generation of eggs hatches in mid to late summer. Trees may suffer no permanent damage beyond being unsightly. If you cannot tolerate the worms and their mess, further treatment methods are outlined in the UC Pest Note on California Oakworm.

    - April
  • Peach Leaf Curl Diagnosis -

    It is too late for chemical control of Peach Leaf Curl in April. If your trees are susceptible, make a note to apply a copper-based spray after this year's leaves drop, and possibly again (for severe problems) in February before the spring bloom. This year’s damaged leaves will eventually fall off and should be disposed of in the trash. The new leaves that are produced are generally fine, but the vigor of the tree may suffer. For more information see the UC Pest Note on Peach Leaf Curl.

    - April
  • Fire Blight -

    Late spring and early summer are the time fire blight shows itself. Fire blight is a bacterial disease that makes plants look as though they have been damaged by fire. It attacks apples, pear and quince, most often, but can also infect ornamentals, such as toyon and pyracantha. Very often, the growing tip folds over into a shepherd’s crook shape.

    Fire blight spends the winter in cankers or wounds on the plant and resumes bacterial growth in the spring. There may be oozing from the canker. It is spread by insects, rain, or pruning. Infection can extend into limbs, trunks, or the root system and can kill the tree. Complete removal of any diseased tissue is critical. Dip clippers into a 1 part bleach, 9 parts water solution between each cut to prevent reinfection. The final cut should be 8-12 inches below the diseased area. The UC Pest Note on Fire Blight contains photos and more information.

    - April, May, June
  • Mosquitoes -
    Make sure you don’t have any water sitting around from our late rains. Mosquitos breed in standing water and can pass along deadly West Nile Virus to people. Check and dump water from any buckets, pots, saucers, dishes, or wheelbarrows. Put containers away or turn them over to avoid collecting additional water. Keep chemicals balanced in swimming pools. Ponds, fountains, and bird baths can also be breeding grounds. Add mosquitofish to these bodies of water to eat mosquito larvae. They are an environmentally friendly means of control and are available free of charge from Santa Clara County Vector Control.
     
    More Information: Mosquito Management
     
    - January, February, March, April, May, October, November, December

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