Pests and Diseases - Problems for the Plants
Unit 5: Monday, May 3, 1999
Friday, May 7, 1999
Monday, May 10, 1999
Friday, May 14, 1999
Be Ready, Problems Will (Probably) Happen
We would all like our plants to grow perfectly, look beautiful and be healthy until the crop is ready to eat. But gardening usually doesn't happen that way because we are working with nature. Many other living things - mostly bugs and fungus - eat or live on plants. That's just part of nature. We need to figure out, as best we can, how to protect the plants and keep them as healthy as possible. We also need to understand that problems with pests and diseases will probably happen because it's a natural process.
Prevent Problems If You Can - Keep the Plants Healthy
By using hydroponics you have already eliminated some garden problems that come mainly from the soil, but your plants depend on your care. You have learned about the water, nutrients and pH necessary for your plants. Be sure to keep these at the proper levels. Plants will survive some problems with pests and disease if they are healthy and strong.
Check other growing conditions such as proper light and air ventilation. Wind and rain conditions should also be checked. It's hard to have a perfect place for your plants, but use the best place available.
Follow the assignments closely. Try not to be careless or let your responsibility slip. A regular time is needed to check the garden and take care of the water, nutrients and pH when it's needed. This will keep your plants as healthy as possible. Then, when pests and diseases happen, healthy plants will have a chance to continue growing.
Observe Your Plants Carefully and Often. Find Pests and Diseases When They Begin.
As part of your regular care, look carefully at your plants. Check all the parts: roots, stems, leaves (both sides), flowers and fruits. Look for problems that show up as spots, holes, or bumps. Is an insect or spider living on the plant and causing damage? You might see fuzzy-looking or discolored places, and droopy leaves. Is it fungus or mildew? If you SEE a problem when it first starts, you might be able to prevent more damage and keep the plant healthy.
The habit of observing and recording problems is used by farmers, experienced gardeners and plant scientists. It gives basic data needed to keep plants as healthy as possible.
Research Information to Identify Problems and Learn About Them
If you see a problem, try to figure out what it is. Insect? Fungus? Nutrients? Growing conditions? To identify problems you'll need a lot of information.
Go back and review the information you already have about nutrients and the growing conditions needed for your plants. Know what the plants must have to grow properly.
In addition, you need to do research and learn about common insect pests and diseases that might attack you plants. Start with what you already know from science classes and other experiences. Talk to friends and other people about pests and diseases in gardens. People can be good help, but check what they say to be sure it is correct. Finally, learn more by finding and studying information sources at websites and in books. Keep these information sources handy so you can refer to them for detailed information when you need it.
1. Insect Pests
2. Diseases - Fungus, Mildew and Mold.
On the Crop Knowledge Master screen, click on Lettuce. (Later when you're growing other kinds of plants, you can come back and check this site.)
Read through the list of insects that attack lettuce. Notice the names and groups, but don't worry too much about the scientific name for this project.
This activity will help you learn about reference books and on-line sites to get detailed information on pests and diseases. You will also be adding to your own knowledge which will help you identify problems you see on your plants.
For each of the resources listed below, do the following things:
Title your report "Sample Facts About Insect Pests, Diseases"
PP. 102 - 154. Bugs, Slugs & Other Thugs, Controlling Garden Pests Organically, by Rhonda Massingham Hart. Storey Publishing, 1991. ISBN 088266-664-9.
PP. 95 - 101 Beginning Hydroponics; Soilless Gardening, by Richard E. Nicholls. Running Press, 1997. ISBN 0-89471-741-3.
PP. 71 - 107. Garden Pests & Diseases. Sunset Publishing, 1993. ISBN 0-376-03302-9
Please note that these sources are written for adults. Students should get help with difficult vocabulary and meaning.
Also, please note that poisons such as Malathyon are mentioned. Chemical poisons should NOT be used for this project. Safe treatments and controls for problems are a topic later in this section.
The books listed can be found at your school library or the Public Library and at book stores. The site facilitator can help you find them. Other books or websites can be substituted, but be sure to give the title, author, date and pages of whatever source you're using.
Now that you have done these activities, you should be able to identify problems that might damage your plants. Keep these information sources throughout this project so you can use to them if you need to.
Decide on a Control or Treatment to Prevent Further Damage
The information sources you explored included some suggested treatments and controls for pests and diseases. Please, remember that when working with nature, you cannot expect to prevent or stop all damage. But many times you can find effective ways to help your plants stay healthy.
In this project we will use organic methods to control problems. Chemical pesticides should NOT be used because they can be difficult and dangerous to handle. Also, short-term controls with chemicals are often outweighed by longer-term bad effects in the environment. Strong natural insecticides such as rotenone, pyrethrum, nicotine, sabadilla and neem should also NOT be used for this project.
They can be toxic to sensitive human beings so crops cannot be eaten for several days. Fish and all insects - including beneficial ones like ladybugs - are destroyed by many of these strong natural pesticides.
When a problem is identified, consider the controls and treatments listed in the information sources you have read. Removing pests by hand, gently washing the leaves or cutting away diseased parts of the plant may be the best treatment. Be sure to wash hands and tools often so problems are not spread by the fingers or blades. Insecticidal soaps, commercial or home made, can be used safely, but cautiously. Some plants, like cucumbers, can be damaged by soap spray. Find reliable information or test the spray on one plant before using soap.
For general information on organic pest control, read pp. 92 - 101 in Bugs, Slugs and Other Thugs by Rhonda Massingham Hart.
Some excellent organic methods of controlling pests and diseases are complicated and best suited for long-term hydroponic gardening. For example, covering plants with screen held on a sturdy frame protects plants from flying insects. However, building the cover is probably beyond the amount of work that can be done of this project.
With some luck added to careful observation, well researched information and thoughtful treatments, it is hoped that you'll be able to minimize damage from pests and diseases. Look forward to a good harvest from your plants.
Mosquitoes, An Annoying Pest
Mosquitoes may become a problem pest for you, not your plants. They lay their eggs in non-moving water such as used for non-circulating hydroponic growing systems. The mosquito population may be high and become annoying. One possible control is to place mosquito fish in the nutrient solution to eat the larvae.