Pests and disease leave tell-tale signs on the plants and trees they infest. It’s up to us to recognize the signs and discern what the problem is and decide on the best treatment. Most of this knowledge will come from a little research and a lot of trial and error.
Pest and disease management will always be an ongoing process in the garden and landscape. These issues also occur with house plants, so if you have any type of vegetation growing indoors or outdoors (including grass), you need to learn a few basics for identifying pest and disease problems.
Look At The Leaves
The leaves are usually the first part of a plant to show signs of a problem. If plant leaves wilt, turn pale green, yellow, develop holes, or curl up on the edges, the plant is showing you it has a problem.
If the growth of a plant is not progressing normally and the plant seems stunted, that’s a sign of a pest infestation or disease. A healthy plant will grow taller, wider, and put on whatever type of produce it’s supposed to throughout the growing season.
Gnarly apples, cat-face tomatoes, yellow cucumbers, or any other fruit, vegetable, or flower that does not look like it’s supposed to have probably been exposed to pests or disease.
Occasionally there will be a produce oddity found in the garden, like a giant head of cabbage or triplet squash, but abnormalities in the shape, size, or color of the produce typically indicate a problem.
Mold, mildew, sour soil, and certain pests and disease produce a foul smell. If you smell an unpleasant odor while tending to your garden, inspect the nearby plants. If the roses, tomatoes, corn, soil, etc. does not smell like it should, something is wrong.
This disease attacks many vegetable, fruit, and flower plants and causes the leaves to have a ‘mosaic’ coloration. The leaves become mottled with yellow, white, and light or dark green spots and streaks. The plant will be stunted and develop deformed leaves and produce.
Cucumbers, cauliflowers, tomatoes, and squash are the most vulnerable to this disease, but there are several strains of this virus and no plant is immune. Plant disease-resistant varieties to help prevent the mosaic virus.
Blossom End Rot
This is a common disease that strikes eggplant, pepper, squash, and tomatoes. It is identified by the tissue of the blossom end of the vegetable breaking down and rotting. It typically starts as a small black spot on the bottom end of the vegetable that continues to expand.
Stop the spread of blossom end rot by removing all affected produce and help prevent it by adding Epsom salt to garden soil.
Powdery mildew is a common fungal disease in gardens, infecting a wide variety of plants and reducing the quality of flowers and fruit. It’s a white fungus that looks like someone sprinkled talcum powder on the plant.
Powdery mildew is spread by the wind and is simple to get rid of if caught early. Increase the amount of sunlight the plants are receiving and spray them with a DIY fungicide. Spray plants thoroughly, as the solution will only kill fungus that it comes into contact with.
DIY Fungicide Recipe:
Mix the following in spray bottle:
- 1 teaspoon baking soda
- 1 quart of water (946 ml)
These small, soft-bodied pests feed on plants by sucking the nutrient-rich liquids out. They are about the size of a grain of rice and congregate on the underside of leaves, especially new-growth leaves. Aphids multiply rapidly and can weaken plants significantly and cause developing produce and flowers to become stunted.
Look for misshapen, curling, stunted, or yellowing leaves. Leaves or stems will also be covered with a sticky substance, called honeydew. This honeydew is a sugary liquid produced by the aphids as waste and it attracts other pests, like ants.
Aphids are easy to blast off plants with a spray of water from the garden hose.
Squash Vine Borer
If a healthy squash, pumpkin, or other healthy gourd vine suddenly begins to wilt, it’s probably the work of a squash vine borer. This garden pest is a type of moth that lays its eggs at the base of squash plants. When the eggs hatch, the larvae bore into the lower stems of the plant, weakening or killing it.
The adult squash vine borer is a moth about ½ inch (1.25 cm) long. It has a gray or black body, marked with orange-red on its abdomen, legs, and head. The hind wings are transparent and the front wings are metallic green.
Use the DIY insecticide to get rid of the moths, or pick them off by hand before they have a chance to lay eggs. Once the eggs have been laid, there is little that can be done to save the plant. The tiny eggs will be in a cluster, hidden at the base of the plant, and as soon as the eggs hatch the larvae bore their way into the squash vine. Eggs will hatch in 1-week after being laid.
DIY Insecticide Recipe for Squash Vine Borer
- 1/2 cup of dishwashing liquid
- juice from 1/2 of a lemon
- a gallon (3.78 L) of water
- spray bottle
Mix the dishwashing liquid and lemon juice into the water. Pour the DIY insecticide mixture into a spray bottle and spray it on plants as needed.
These are soft-bodied, winged insects that can be found in almost any region, but they are so tiny that they are difficult to see. Whiteflies are 1/12 of an inch (1.25 cm) long, white in color, and triangular in shape, and are found clustered on the undersides of leaves.
When whiteflies infest a plant, the plants will quickly become weak, leaves wilt, turn pale or yellow, and growth will be stunted. These pests also leave behind honeydew like aphids, that attract ants.
Use whitefly traps or the squash vine borer DIY insecticide.