Whether you're growing perennials, annuals, bulbs, roses, trees,
shrubs, lawn, fruits, vegetables, herbs, or house plants, it's a fact
of life there are insects and diseases that cause damage to plants.
Here in western Massachusetts we have our fair share of both insects
and diseases. Insects and diseases in our area range from the fairly
innocuous to those that pose a severe threat to plants.
Insect pests that cause damage to perennials, annuals, and bulbs
include thrip, nematode, cutworm, slug, snail, Japanese beetle and
other beetles, red lily leaf beetle, leafminer, mite, fourlined plant
bug, aphid, caterpillar, ant, leaf hopper, whitefly, spittlebug,
earwig, weevil, nematode, iris borer, and grasshopper.
Roses are bothered by many insects including aphid, thrip, beetle,
caterpillar, mite, leaf hopper, and scale.
Trees and shrubs have their share of insect pests that cause serious
damage including borer, hemlock woolly adelgid, mite, beetle,
caterpillar, aphid, scale, lacebug, leaf hopper, plant bug, thrip,
mealybug, whitefly, weevil, leafminer, leaf roller, sawfly, psyllid,
midge, and nematode.
The lawn comes under attack by many insect pests including grub, sod
webworm, chinch bug, and ant.
Insects that bother fruits include borer, psyllid, scale, aphid, ant,
caterpillar, beetle, mite, fruit fly, nematode, apple maggot,
curculio (a type of weevil), and leaf roller.
There are many insect pests that attack vegetables and herbs
including tomato hornworm, striped cucumber beetle, spotted cucumber
beetle, imported cabbage worm, cabbage looper, European corn borer,
corn earworm, carrot rust fly, squash vine borer, squash bug, Mexican
bean beetle, Colorado potato beetle, asparagus beetle, nematode,
cutworm, whitefly, flea beetle, slug, snail, earwig, grasshopper,
mite, leafminer, caterpillar, beetle, leaf hopper, aphid, pillbug,
cabbage maggot, onion maggot, thrip, and wireworm.
Insect pests that bother house plants include mealybug, whitefly,
aphid, scale, spider mite, fungus gnat, and thrip.
There are many different types of plant diseases, but some of the
most common and damaging ones here in western Massachusetts include
powdery mildew, rust, and early blight.
Powdery mildew is probably one of the most prevalent plant diseases.
It affects all different types of plants both in the garden as well
as indoors on house plants. Powdery mildew forms a white, powdery
coating on plants' leaves and stems. It's a fungus that is spread by
rain, watering, and even wind. The spores overwinter in the soil and
splash up onto the lower parts of plants when it rains or while
watering. The disease spreads up the plant, coating the leaves and
stems. It often causes the leaves to drop off the plant. In the
garden, powdery mildew can attack just about any plant, but it's most
often found on rose, lilac, monarda, tall garden phlox, aster, wax
begonia, dahlia, squash, and zinnia. Powdery mildew also affects
house plants including begonia, African violet, streptocarpus, and kalanchoe.
Rust is another fungal disease that is a serious problem of many
garden plants. It causes small, round, rust-colored or brown spots
that appear on the undersides of leaves as well as on plant stems.
Leaves become dry and die. The disease weakens the plant and causes
its growth to be stunted. Plants with severe infections can die. Rust
spores overwinter in plant debris as well as on trees. Infection
begins in spring as the days become warmer, but nights remain cool.
Rust spreads from plant to plant during wet weather. Leaves that
remain wet for long periods of time are susceptible. The spores are
also spread by wind and can travel many miles to infect healthy
plants. Rust attacks rose, zinnia, hollyhock, geranium, annual aster,
chrysanthemum, dianthus, iris, fuchsia, sunflower, cedar, fruit
trees, grape, birch, mountain ash, asparagus, and bean.
Early blight is also a fungal disease that causes severe damage,
especially to tomato plants. It begins as small, irregular brown
spots on the leaves. The brown spots have many concentric rings in
the center. The spots have a yellow outer edge and when there are
numerous spots on a leaf, the entire leaf can turn yellow. Once the
entire leaf is affected, it drops off. The disease starts on the
lower leaves and eventually makes its way up the plant, even spotting
the fruit. The disease is at its worst as the fruit is maturing. In
severe cases, it causes most to all of the leaves to drop, weakening
the plant. It also reduces the size of the fruit and leaves the fruit
susceptible to sunscald since there's no foliage left to shield it
from the sun. Spores of early blight overwinter in plant debris and
are most active during humid, warm weather. In addition to tomato,
early blight also affects pepper, celery, and potato.
Fortunately, there are effective, organic treatments for just about
every insect or disease that affects plants. Depending on what the
problem is, gardening products I'll use include Neem
Oil, Milky Spore Powder Grub Control,
and Diatomaceous Earth.
Click on a product name to read more about it and order it from
Pernell Gerver's Online Store.