Mealybug destroyer identification

Like their close cousin, the lady bug, mealybug destroyer adults have the same dome-shaped body and short, stubby antennae. [That's a pretty cute little face, too, wouldn't you agree?] Mealybug destroyers, however, have black wing cases (elytra), with orangish-brown shoulders and rear end. Adults are only 1/6 of an inch log, so you may never notice them. If you decide to take a closer look with a hand lens, you might be able to see that females have dark brown forelegs and males’ forelegs are light brown. The larval forms, which can reach 1/2 inch in length, are often mistaken for wooly aphids or mealybugs, because of their elongated, alligator shape and waxy, white filament covering. Yellow eggs are laid near mealybug eggs for easy access to their favorite food supply.

Mealybug destroyer diet

A single mealybug destroyer may eat 250 mealybugs in its short lifetime. They also feed on soft scale insects. And it is not just the adults who hunt down and kill our garden enemies. While adults chomp and chew, larval forms pierce and suck the life juices from many sap-sucking garden pests.


Mealybug damage

So, why would a gardener care about mealybugs? Cousin to aphids and whiteflies, mealybugs are sap eaters. They feed on new buds, shoots, and leaves, causing erratic or reduced budbreak, slowed growth, and twig dieback. Mealybugs are frequent pests to basil, grapes, stone pine, pomegranate, chamomile, apple, plum, pear, peach, ferns, orchids, and, well, quite honestly, pretty much everything growing inside or outside of your home. Mealybugs produce honeydew, which provides the perfect growth medium for sooty mold. They can also carry bean mosaic. That’s why.


Attracting mealybug destroyers

It is highly unlikely that there are any mealybug destroyers in your neighborhood to attract. They simply cannot handle winter weather. So, you will probably have to buy mealybug destroyers each spring. What you can do, to prevent them from flying away as soon as they arrive, is to provide biodiversity. This means installing a wide variety of plants, with various heights, shapes, and colors. And avoid those broad spectrum insecticides.


Mealybug destroyers may not occur naturally in the Bay Area, but they sure can help maintain the balance of power in your foodscape!

Flea beetles hop from plant to plant, chewing tiny holes in leaves as they go.


We are not talking about the blood-sucking, disease-carrying fleas on squirrels. Instead, flea beetles are plant pests. Generally, they do not cause a lot of damage. After all, each flea beetle is only 1/16 to 1/8 of an inch long! If your plants are hosting enough of them, however, the damage can slow growth or provide points of entry for bigger problems. Let’s see what your plants are up against.


Flea beetle varieties
​
There are dozens of leaf beetle species. Here in the Bay Area, you are more likely to see these particular pests:

• tobacco flea beetle (Epitrix hirtipennis) - brown with black markings
• western black flea beetle (Phyllotreta pusilla) - dark olive green or shiny black
• western potato beetle (Epitrix subcrinita) - shiny black or bronze
• western striped flea beetle (Phyllotreta ramosa) - black with curved yellow or white stripes

Flea beetle host plants

Flea beetles feed on many families of edible garden plants:

• legumes - Lima beans, cowpeas, fava beans
• Brassicas - cabbage, Brussels sprouts, bok choy, rutabaga, kale, radishes, watercress
• Cucurbits (gourds) - watermelon, zucchini
• Solanum (nightshade family) - tomatoes, eggplant, tomatillos, peppers

Also, carrots, corn, and sweet potatoes may find themselves on the menu. Flea beetles are also attracted to yarrow, but this is a good thing. Yarrow acts as an insectary. Beneficial insects have evolved to lay their eggs in plants such as yarrow, knowing that flea beetles and other pests will provide their young with an easy first meal. Other beneficials, such as big-eyed bugs, will also feed on flea beetles, so go easy on the pesticides. Pesticides don’t work very well on flea beetles anyway - they simply hop away.


Flea beetle damage

Pitting and small, irregular holes in leaves may merge to create raggedy areas. The holes are smaller than the damage caused by shot hole disease. Shot hole disease holes usually begin as 1/10 to 1/4 inch diameter red or purplish spots. There may be a pale green or yellow ring around each spot. As the dead tissue dries up and falls away, the shotgun blast look will appear. Small, irregular leaf holes may be caused by springtails, but it is more likely to be flea beetles. Fruits and roots may also be damaged by flea beetles.


Flea beetle lifecycle

Flea beetles lay tiny eggs in weeds, plant debris, and in the soil surrounding their favorite food plants. After the eggs hatch into thin, white larva, feeding may begin above or below ground. After a month or so, the larva pupate in the soil. When they emerge as adults, they use their big jumping legs to go wherever they want to feed.


Flea beetle control

Since pesticides are not very effective on flea beetles, other controls must be used, if control is actually needed. In most cases, it isn’t. If an infestation starts to cause serious damage, use basic sanitation in the garden. Removing all those tiny hiding places can make life difficult for flea beetles. Reflective mulch and white sticky traps can also be used, and row covers may block pests from reaching plants in the first place. Once they are present, you can lightly sprinkle the area with diatomaceous earth (DE). Apparently, flea beetles don’t care too much for sulfur, either.


Some commercial growers actually vacuum off heavy flea beetle infestations, but I don’t recommend it for the home gardener. You vacuum cleaner would never be the same!

Hummingbirds

We may love to see hummingbirds flitting through the garden, but you should be aware that hummingbirds may carry flower mites. Flower mites are tiny, nectar stealing pests that run up a hummingbird’s beak as it feeds. Grabbing ahold of the hummingbird’s nostrils, flower mites then go for a wild ride in hopes of reaching a new food source. When the hummingbird stops to feed at a different flower, the mite runs down the hummingbird’s beak to gorge on as much nectar as it can before hopping another ride to yet another flower.


Honey bees

Moving in the opposite direction, it has recently been discovered that varroa mites, the bane of honey bees, are phoretic. These devastating parasites of the honey industry lie in wait for unsuspecting honey bees to visit a flower. As the bee collects nectar and pollen, varroa mites catch a ride that ultimately takes them to the hive. These parasites suck the life fluids from developing and adult bees. These pests also carry viruses that infect honey bees. Varroa mite infestations can kill an entire hive, if left untreated. Varroa mites are just one aspect of the global problem of colony collapse disorder.


Ground bees

Male ground bees are seduced by blister beetle larvae into carrying them to female ground beetles, phoresy style. Blister beetle larvae emit a pheromone that is similar to the perfume used by female blister beetles to attract males. When male ground bees approach, the blister beetle larvae attach themselves to the male bees. After recovering from their disappointment, the male bees continue their search for a female. When she is found, the male bee blindly does his business as the blister beetle larva moves to the female bee. When she returns to her nesting area, the larva jumps off and begins feeding on everything it can - nest, provisions, and eggs.

Clubroot is not the newest bar in town; it is a disease of many fall and winter crops.


Clubroot, or club root, is caused by an imported plant parasite that grows inside of plant cells. This parasite used to be classified as a slime mold, but is now in an entirely different category, called Phytomyxea. This pathogen is called Plasmodiophora brassicae, but don’t let the name scare you off from learning about it. The brassicae part of the name tells you which plants are susceptible: members of the cabbage family. The Plasmodiophora part of the name tells us that these are mouthless, amoeba-like plant parasites.


Which plants are affected by clubroot?

Clubroot occurs in nearly all members of the brassica family. This means that your broccoli, Brussels sprouts, cabbages, cauliflower, radishes, and turnips are susceptible. In addition, alyssum, mustard, nasturtium, and wallflowers, as brassicas, can also become infested with this parasite.

Don’t get your hopes up. Chocolate spot is a fungal disease that attacks fava and other broad beans.


Chocolate spot is caused by the Botrytis fungi, a family of fungi responsible for grey mold on practically everything. Chocolate spot, in particular, is caused by Botrytis fabae.

Chocolate spot symptoms

Moist conditions cause small reddish-brown spots to form on leaves and pods. These spots expand, leaving a dead, gray center. The fungi can spread so much that leaves and pods are aborted. And they certainly don’t look very appetizing!


How to control chocolate spot

As always, avoid overhead watering on plants susceptible to fungal disease. Black aphids are suspected carriers of the fungi that cause this disease, so controlling aphid populations may help. These fungi can overwinter in the soil and on decaying plant debris. Be sure to remove any infected plant material completely from the garden to avoid spreading the disease. Fungicides have been used to control chocolate spot, but timing is critical.

Carrot beetle damage

Carrot beetles (Ligyrus gibbosus) feed both above and below ground. They attack sunflowers, carrots, lilies, iris, and dahlia. Taproot feeding causes yellowing foliage (chlorosis), stunting, plant collapse, and death. Feeding damage may also be seen on lower (basal) leaves and stems.


Carrot beetle control

Adult beetles fly at night and are attracted to lights. You can reduce infestation by using row covers and keeping the garden unlit at night. You can also reduce hiding places by keeping mulch and decaying plant matter away from susceptible plants. Insecticides have not been effective at controlling these pests.


Adult carrot beetle (Frank Peairs)
https://www.forestryimages.org/browse/detail.cfm?imgnum=5364197

Dodder is too bizarre for words.


This plant doesn’t even look like a plant. It looks more like a fungi, or an alien!


Thin yellow, red, or bright orange threads emerge from the ground and start twining around and draping over everything in sight. Everything, that is, if you’re a plant. Dodder (Cuscuta) is a parasitic annual. It gets most of its nutrition by inserting a straw-like structure, called the haustoria, into the plants it covers. Some species of dodder can perform a limited amount of photosynthesis.

The dodder plant

If you look closely, you can see that dodder seedlings are rootless, leafless stems. As the dodder plant matures, it may produce small, triangular leaves that look like scales. Tiny, bell-shaped, cream, pink, or yellow flowers may also be seen, but it is the extensive web of threads that will really catch your eye!

Bacterial wilt is a disease that causes members of the gourd family to wilt.


Bacterial wilt is caused by a bacterium called Erwinia tracheiphila. It mostly affects cucumbers and muskmelons, but it can also infect pumpkins and squash.


Symptoms of bacterial wilt

Damage caused by bacterial wilt looks a lot like feeding damage caused by squash bugs. As the bacterium begin to multiply within vascular tissue (veins), they clog the xylem, which makes the plant wilt. The sap of an infected plant will be milky colored and able to create a viscous string. (Ew!)

Disease carriers

Striped and spotted cucumber beetles carry this disease. The Erwinia bacteria that cause this disease can live in the gut of their carriers for quite a long time. The bacteria can be transmitted as these pests feed and through contact with frass.


Bacterial wilt treatment​

Unfortunately, there is no effective treatment. Once a plant is infected, it is too late. Since the infected plant poses a health risk to its neighbors, it should be removed and thrown in the trash. Any tools that came into contact with the plant should be sanitized in a solution of one part bleach and nine parts water. Bathroom disinfectant can also be used. To reduce the chance of infection, controlling beetle populations and maintaining healthy plants are your best bet.

Oleander aphid description

Like other aphids, this species is small (1.5 to 2.6 mm), pear-shaped and soft-bodied. Oleander aphids, in particular, are bright yellow, with black legs, wings, and cornicles. Cornicles are tiny spikes on an aphid’s back that can excrete defensive fluid. [My dog did that once, after he got into some old pork bones. It wasn’t pretty.] Actually, these defensive fluids are cardiac glycosides that the aphids take from their host plants! Cardiac glycosides are known heart poisons. Luckily, these pests cluster on new stems and are easy to spot. And those defensive fluids won’t hurt you.


Aphid lifecycle

As much as I dislike aphids for their plant-damaging and disease-carrying capabilities, I have to give credit where it is due. These soft-bodied bugs really are amazing. Female aphids (and almost all of them are female) are viviparous and parthenogenetic. Wait! Come back! Let me explain. Viviparous means that offspring develop within the mother, the way we do. Parthenogenetic means fertilization by a male is not needed to produce offspring. Not like us. Most aphids do not have wings. But, when they become too crowded, or when a plant starts senescing (dying), some adult aphids emerge with wings. That would be something like all human beings being born 40% smaller, simply because we start running out of room and resources. Hmmm… But I digress. Let’s get back to aphids.]


Oleander aphid damage

Like other sap-sucking insects, oleander aphids pierce plant parts to tap into the phloem of the host plant. Think of it as diabetic mainlining. This nutrient rich food source blows through an aphid’s body, creating a sticky sweet residue called honeydew. Honeydew is a petri dish for bacterial and fungal growths, such as sooty mold. Also, the aphid tendency to feed in clusters stunts growth and deforms flowers and leaves, crippling milkweed and oleander plants. Vinca, periwinkle, and frangipani are also affected.

Katydids are cousins to crickets, grasshoppers, and mole crickets, and you do not want them in your garden or landscape.


There are over 250 different species of katydid in North America (over 2,000 species worldwide). The name ‘katydid’ refers to the sound made by males when they are trying to attract receptive females.


Katydid identification
Katydids can be difficult to see. It’s not that they are small, because they aren’t. Mature katydids can range from 1/2” to nearly 5” in length! The difficulty lies in their resemblance to leaves and the fact that they are mostly nocturnal. During the day, they hide out in trees and shrubs, blending with the foliage. They tend to have a bright green, blade-like body, with large hind legs. They look a lot like flattened grasshoppers, but with extra long antennae (or ‘horns’). Very often, the only notice you will get that katydids are present is the damage they cause and a male’s strident chirp.

Katydid lifecycle

Katydids (Tettigoniidae) start out as oval-shaped eggs that are laid in rows, at the end of summer, in the soil and in host plant stem holes. These eggs often hatch out looking like tiny adult katydids with big heads and small wings. Nymphs of some species of katydid mimic spiders or leaf-footed bugs in their early stages of development to avoid being eaten. As they feed and grow, they shed their outer exoskeleton and go through several instars before reaching adult size. As summer nears its end, males start singing to attract females. Females use the volume and fluency of a male’s chirp to judge his fitness level. In order to ensure a healthy pregnancy for the female, male katydids provide their (temporary) mates with a ‘nuptial gift’ of sperm and highly nutritious food.

Buffalo hopping from tree to tree? The image made me laugh, so I decided to make this pest the Garden Word of the Day.


Buffalo treehoppers (Stictocephala bisonia) get their name because they have a triangular head that looks like a buffalo in profile. Sort of. These native pests are only 1/4 inch long and bright green to brown. Because of the color and shape, they are difficult to see. Some individuals develop a horn-shape to the head that looks like a thorn. You can walk right up on one and not even know it’s there, until it leaps into the air and flies away.

Buffalo treehopper lifecycle

Every summer, male buffalo leafhoppers take to the trees and sing their tiny hearts out, but we can’t hear them. If we could, they would sound something like cicadas, or crickets. His song attracts females for the normal reproductive activities. Late summer through early autumn, females lay eggs using a blade-shaped ovipositor that cuts a series of slits in twigs and stems. Each cut may contain a dozen eggs. The next year, in late spring, nymphs emerge. They look like miniature adults, but with feathery spines. After several molts, they emerge as adults.


Damage caused by buffalo treehoppers

Well, they break off entire branches, right? Just kidding. These small pests begin their destructive behavior during the nymph stage when they drop to the ground and feed on grasses and herbaceous plants. As they mature, they begin feeding on many different fruit trees, particularly apple, pear, cherry, prune, and quince. They also feed on ash, hawthorn, elm, and locust, and a wide variety of herbaceous (non-woody) plants.

The heady aroma of summer nectarines and peaches means it’s time to be on the lookout for peach twig borers.


While examining my nectarines for ripeness, I spotted a reddish-brown larva with white bands undulating across a twig. Of course, I picked it up and dropped it in a little plastic bag and sealed it up tight, until I could look it up. That’s what I learned that even the nicest tree cage has its limits.

Peach twig borer control

Tachinid flies and braconid wasps provide natural controls. When that isn’t enough, you can spray environmentally sound insecticides, such as Bacillus thuringiensis (Bt) or spinosad, just as blossoms appear, for added peach twig borer control. Dormant oil can also be used in winter, when combined with the same insecticides, to kill off the overwintering larvae. The oil will not kill peach twig borers by itself. Pheromone traps can be used to interfere with mating and to monitor for these pests. Just be aware that hanging a pheromone trap can actually attract pests to your trees if handled incorrectly. Read the label.


So, as you check your nectarines and peaches for ripeness each summer, be on the lookout for these tiny pests. Also, add preventative treatments to your garden calendar while you’re thinking about it.

The summer song of crickets and grasshoppers provide many of us with a comforting reminder of childhood. If you are a gardener, your might hear those sounds with different ears.


Cousins to katydids and locusts, crickets (Gryllidae) and grasshoppers (Acrididae) are members of the Orthoptera family.


Characteristics

Both crickets and grasshoppers have a large head, long saltatorial* back legs, for jumping, a cylindrical body (pronotum), compound eyes, and a mouth able to bite and chew. They have two pairs of wings: the forewings (tegmina) and hindwings. Beyond those similarities, there are many differences:

• Crickets have long antenna, while grasshopper antenna are short.
• Grasshoppers chirp by rubbing their wings against their legs, while crickets only rub their wings together.
• Crickets’ ears are at the bottom of the abdomen, while grasshoppers’ ears are in their tibia (front legs).
• Grasshoppers prefer coming out in the daytime, while crickets are ‘crepuscular’, which means they prefer evening, and nocturnal.
• Crickets are omnivores, while grasshoppers are herbivores.

Lifecycle of crickets and grasshoppers

Both species start out as eggs that were laid, in late summer and early fall, in the top 2 inches of soil, in clusters of 20 to over 100 eggs. In spring, these eggs hatch as nymphs, which begin feeding on nearby plants. When those food supplies are exhausted, they look for new places to feed, generally downhill from where they started. Grasshoppers will molt 5 or 6 times as they outgrow their exoskeletons, and crickets molt 8 or more times. There is no pupal stage, so these insects are said to go through incomplete metamorphosis.


Crickets

There are house crickets and field crickets. Both are collective terms for several different cricket species. All of them feed on seeds and plants, along with grasshopper eggs, moth and butterfly pupae, flies, and spider sack lunches. House crickets (Acheta domesticus), sold as lizard food, are usually brown or tan, and one inch long or less. Field crickets are slightly larger than house crickets and they are usually black.

Grasshoppers

While there are over 200 different types of grasshoppers in California, only two cause significant damage: the valley grasshopper (Oedaleonotus enigma) and the devastating grasshopper (Melanoplus devastator). Most grasshoppers can fly.

Bacterial speck may sound redundant - we all know bacteria are tiny - but bacterial speck is a bacterial disease of tomatoes that can be controlled with a speck of good cultural practices.


Bacterial speck looks a lot like bacterial spot and bacterial canker, but it is less likely to be fatal. All three diseases appear as small brown or black lesions on leaves, stems, and fruit. These lesions may merge into larger, irregularly-shaped areas. There is normally a yellow halo around these lesions and the interior tissue dies rather quickly. Most of these lesions are found near leaf edges (margins). On fruit, the lesions look like tiny black bumps.

Bacterial speck lifecycle

Bacterial speck is caused by Pseudomonas syringae pv. tomato, a cousin of the bacteria that cause angular leafspot, citrus blast, and leaf spot. This bacteria is found in soil and on seeds. Seeds from diseased fruits should not be planted the following season, or you will simply continue the process in your garden. These bacterium can remain dormant for a very long time, until the weather turns cool and damp. Then they start growing like crazy. The bacteria are frequently splashed onto leaf surfaces by rain and overhead watering.


Bacterial speck control

Fixed copper sprays and good air circulation are your best preventative measures. You can also delay spring planting until after temperatures warm up, and avoid overhead watering.  Properly spacing plants can reduce the spread of infection.


Diseased fruits are safe to eat, simply cut out the infected areas and toss them in the trash (or feed them to your chickens). Diseased plants should not be composted. Instead, toss them in the garbage to reduce the likelihood of reinfection.

Blight is a symptom of plant disease.


One day, your plant looks lush and healthy. The next day, several leaves are yellow and then turn brown. Stems, flowers, and branches also turn brown and then die. What can cause this sudden, severe damage? It might be blight.

Blight is a symptom

Blight is not a disease. It is what several different plant diseases look like. The initial symptoms appear suddenly and spread very quickly. Leaves, fruit, stems, and flowers can all be affected. The first symptom is tiny lesions on leaf tissue. This is where the bacteria or fungi first enter the plant, usually through small tears. The pathogens may also enter through vulnerable new growth. What starts out looking like leaf spot soon covers entire areas of a plant. Leaves and flowers suddenly lose all their green and turn pale yellow (chlorosis), followed by spotting, browning, withering, and dying.

How to control blight

Since blight enters plants through wounds and tender new growth, there are three ways you can reduce the likelihood of blight occurring in your garden:

• protect plants from physical damage
• avoid pruning too heavily
• avoid using too much fertilizer

These are especially important when temperatures of 75° to 85°F are expected to be accompanied by rain. Pruning and feeding stimulate new growth that cannot defend itself. Also, do not irrigate trees while they are in flower. Monitor plants closely after favorable conditions have occurred and completely remove and destroy any infected tissue. This means cutting several inches below infected tissue, using pruners that are dipped in 1 part bleach and 9 parts water between each cut. This reduces the spread of the disease. Blossom sprays can be used on trees that have experienced blight in the past. Fixed copper sprays may provide some protection.​

Plants preferred by leafhoppers

Leafhoppers enjoy many of the same plants that we do. In addition to many woody ornamentals,  such as boxwood, local leafhopper species love to feed on sweet potatoes, squash, beans, horseradish, cucumbers, corn, melons, blueberries, grapes, and beets, just to name a few! Since leafhoppers can carry diseases with them, they put many plants at risk.

Belly rot looks almost as bad as it sounds.


What starts as brown or black mushy areas on the underside of your melons or squashes turns dry and leathery. It won’t hurt you, but it can make fruits more susceptible to other pests and diseases.

Melons, squashes, and other members of the cucurbit family can all get belly rot. Belly rot is a fungal disease caused by Rhizoctonia solani. Infection occurs when fruit is left to sit on the soil for prolonged periods, especially when moisture is present.


Symptoms of belly rot

If you see water-soaked, sunken, black or brown spots on fruit, and it is not blossom end rot, it is probably belly rot. The lesions can be very small to covering the complete underside of a fruit. As the infection spreads, the lesions dry out and become leathery or scabby. Infected fruit should be removed


Preventing belly rot

To prevent the spread of belly rot, avoid overhead watering and get that fruit up off the ground. You can use trellising, tomato cages, children’s furniture, those little plastic pizza box props, straw, benches, colanders - ANYTHING that will allow some air to get between the fruit and the soil. Improving drainage will also make this disease less likely to occur. 


Generally, the fungi that cause belly rot are everywhere, so prevention is your best bet. This means checking the bellies of your melons on a regular basis!

Braconid wasp identification
There are over 12,000 different named braconid wasp species, worldwide, with another 40,000 or so, yet to be identified. Most are dark brown or black with reddish accents. It is estimated that there are 1,700 different braconid wasps in North America and they are all stingless. Braconid wasps can be as small as 1/13 of an inch long, or as big as 5/8 of an inch. If you can get one to hold still while you go find a hand lens, you would be able to see that these tiny wasps have antennas with 16 or more segments! What you are more likely to see are their oblong, white or yellow eggs sticking out of a host insect.

Braconid wasp diet

Adult braconid wasps, while they eat mostly pollen and nectar, are beneficial because they parasitize many garden pests. This means that they lay their eggs on or in other insects. When the eggs hatch, the larvae eat their host. Garden pests vulnerable to parasitization by braconid wasps include:

• leafrollers
• armyworms
• hornworms
• orange tortrix moth
• light brown apple moth
• peach twig, and other borers
• bark beetles
• codling moth
• clearwing moths
• cabbageworms
• cutworms 

Attracting braconid wasps to your garden

Parasitic and predatory wasps are attracted to mixed plantings that provide nectar and pollen, along with insect prey. To make your garden and landscape more appealing to these beneficial insects, be sure to include a wide variety of flowering plants at various stages of development throughout the growing season.

The culprit

Botrytis cinerea is everywhere. It flies in on the wind, it is carried on clothing, shoes, tools, pets; it’s floating around in the air we breath. Yep, it’s like that. So, unless you live in a bubble, your plants and food are already in contact with grey mold. There are actually several different strains of grey mold. They get their Latin name, Botrytis, from the Greek words for ‘grapes like ashes’. You might think that’s because they feed on grapes, but it is actually because the fungi itself grows in clusters. The word ‘ash’ refers to the grey color. ​

Preventing infection

Most commercial grape growers apply fungicides to prevent infection, since the fungi is present all the time. As wth downy mildews, black spot, and powdery mildew, moisture control is the key. If leaves and fruit are left wet, they are more likely to become infected. [Remember those strawberries you washed before putting them in the fridge last night? Yep, that’s what happened!]


Controlling grey mold

Once infection begins, potassium bicarbonate-based fungicides can be applied to reduce the spread of the disease. Dead and diseased plant tissue should be carefully removed. I say ‘carefully’ because each bit can contain millions of fungal spores.


Some people have an allergic reaction to grey mold that causes a rare lung disease known as ‘winegrower’s lung’.


So, the next time you buy strawberries or grapes, wait until you are ready to eat them before rinsing them off. It’s not a guarantee, but it helps! Also, keep them in their container and put them in the crisper drawer. Strawberries are best stored at 32 to 36 degrees F, at 90 to 95% humidity.

Black spots on leaves and petals is a sign of disease.


Spring and summer fogs and dew can leave behind just enough moisture to create breeding grounds for several different bacteria and fungi. While there is a specific disease called black spot, there are other bacterial and fungal diseases that can cause black spots, including citrus blast, common leaf spot, bacterial spot, anthracnose, bacterial speck, and entosporium leaf spot. Black spot mostly attacks roses, but its presence can indicate potential other problems in the garden or landscape.


What are the black spots on my leaves?

Black spots on leaves, fruit, canes, stems, and twigs are areas where a pathogen is breeding and feeding on plant tissue. These black spots are generally round because the infection begins at one point and spreads out equally in all directions. The spots have perforated edges and can reach one-half inch in diameter. As the area of dead tissue expands even larger, it can take on many different shapes. There may be a yellow halo around these leaf spots and yellowing in the surrounding plant tissue.

Black spot: the disease

The black spot disease is caused by a fungus called Diplocarpon rosae. These fungi spread through rain and sprinkler splash, and wind, to tender new growth. This disease usually spreads from lower leaves, moving upward. Tools used on an infected plant can also spread the disease to other plants, so be sure to sterilize tools with a 1 part bleach, 9 parts water solution, or spray tools with bathroom cleaner after each cut when working with a potentially infected plant.


Black spot treatment

Once a leaf is infected, there isn’t anything you can do for it except remove it from the plant and throw it in the trash. Antifungal sprays, such as Bordeaux mixture, can be used to prevent future infection and at the first sign of the disease. Sulfur or diluted neem oil can also be used. Treatments will need to be repeated every 7 to 10 days for as long as temperatures are between 75 to 90 °F.


Preventing black spots
​
As usual, prevention is a lot easier (and more effective) than treatment. These tips can go a long way toward preventing the problem of black spot in the first place:

• remove fallen leaves
• avoid overhead watering
• spray new growth with fixed copper or Bordeaux mixture
• irrigate in early morning to give plant surfaces time to dry out (spores need 7 hours of moisture to reproduce)
• provide ample space between susceptible plants
• prune for better air flow
• apply sticky barriers to block ants from protecting aphids
• spray aphids off plants early in the morning, using a garden hose

Rose image
http://ipm.ucanr.edu/PMG/D/D-WO-DROS-FO.003.html


Tall rose 
http://ipm.ucanr.edu/PMG/D/D-WO-DROS-FO.002.html