WHAT’S BUGGING YOUR GARDEN?
Oh no! The aphids are in my roses! Something is eating my herbs! What’s that white stuff all over my Begonias? My Bougainvillea has big notches chopped out of the leaves but there is nothing there. I thought nothing bothered Bougainvilleas!
Here’s the truth. California was built on an ant hill, there is a new disease or pest entering our state on average each month, piggy backing a ride on a tourist or an incoming shipment of goods. At the bottom of this page, we’ll give you some helpful ideas and links to finding individual pests or disease problems. We’ll try to cover a few here.
Insects are either chewing, sucking, piercing, or just generally fighting on the side of the bad bugs. Sucking insects suck the juices out of the plants leaves or other tissues and make your leaves look pale and dried out. Many insects carry viruses. A virus is a disease and like in people there usually isn’t a cure. There are lots and lots and lots of them. Some are fungal like mildews, some are bacterial and usually cause spots or turn plants black and ugly. If you don’t know what you are fighting, take a sample in a plastic bag to your local garden center and ask for someone who is knowledgeable on plant problems. If they don’t know go to your local Agricultural Home Garden Advisors free helpers. They are called Master Gardeners.
Identify the Insect
Insects that chew through the entire leaf. Damage appears as jagged edges or holes in the leaves. Examples: caterpillars, weevils, grasshoppers
Insects with rasping or sucking mouth parts. Damage causes plant parts to twist, curl or become distorted. Examples: psyllids, thrips
Insects that feed inside the leaves between the upper and lower surfaces. Worm-like larvae causes the damage. Example: leaf miners
Some of these insects protect themselves in a silk covering or roll/curl leaves around their bodies and others may produce a spit-like substance in which to live. Examples: webworms, leafrollers, spittle bugs
Some of these insects chew plant tissue off one side of the leaf while leaving the opposite leaf cuticle and veins intact. Examples: sawfly larvae, Japanese beetle adults
Insects with sucking mouth parts that pull large amounts of fluid from the plant and excrete honeydew. This makes everything below sticky and attractive to other insects such as wasps, ants and flies. Black, sooty mold may grow on leaves covered with honeydew. Examples: aphids, scales
Insects with sucking mouth parts that remove plant juices and leave a dot, fleck or speckle on the leaf surface. Examples: lace bugs, spider mites
Identify the Disease
Common on many ornamentals, this fungus appears as a white powdery growth on the surface of leaves, which can become twisted and discolored; buds can be damaged as well. The disease is favored by dry weather and cool nights, often appearing in the fall.
Black Spot of Rose
Caused by a fungus spread by rainfall, this disease occurs when the weather is humid. Most roses are highly susceptible. Leaves tend to yellow around leaf spots and drop off, defoliating the plant in the worst case.
Brown Patch or Large Patch
Appears as roughly circular patches in the lawn, one-half to several feet in diameter and yellow to tan/brown in color. Irregularly shaped lesions on individual grass blades have brown borders and are tan in the middle. A small amount of gray cottony mycelium may be seen during periods of high humidity or when the grass is wet.
Appears as bleached white to tan or chocolate brown spots in the lawn, from the size of a dollar coin up to 12 inches across. Grass may be killed to the ground, and depressions may grow into one another and form large, blighted areas. Distinct lesions are not always evident on close-cut turf, and the leaves die-back from the tip and turn white to light tan. Grass leaves usually remain upright and have white to light tan lesions with a light red to dark brown border. As the lesions expand, the leaf is girdled and the upper part dies slowly. Short, fuzzy white mycelium may appear early in the morning.
Gray Leaf Spot
Identified by stand thinning and wilt, progressing to yellow to orange patches 4 to 12 inches across, which rapidly coalesce to form larger, irregular areas of damaged turf. Leaf blades are matted and greasy in appearance. Round to oval spots on leaf blades that are tan to gray with a brown border expand with time and girdle the blade, causing it to die-back from the tip down. The spots turn gray and fuzzy (profuse spore production) when the leaves are wet or in high humidity.
Appears as circular to irregular patches, 4 inches to 2 feet in diameter, often with a reddish tint. Patches may merge to form large, irregularly shaped areas of damaged turf. Thick red strands emanate from affected leaves. Small, fuzzy pink tufts may be seen when leaves are wet or in high humidity.