Last modified: Sunday, January 20, 2008 1:59 AM PST Botanical insecticides By Tammy Jones  Neem oil is made from the seeds of the native Indian neem tree, Azadirachta idica.  Neem Neem oil for the most part works as an appetite suppressant on pests but, on others works as a growth or development inhibitor. Aphids, cucumber beetles, mealybugs, mites and more avoid plants treated with this extraction. Then, there are lots of flowers and herbs that have insect-repellent qualities and are valuable as companion plants or in home bug remedies.  Marigold (not the scentless varities), nasturtiums, tansy (not ragwort), rue, feverfew, chamomile, lavender, southernwood and other artemisias, many kinds of mints, especially pennyroyal have insect repellent qualities.  These have all been long relied on for their abilities to repel bugs.  Most cooking herbs can also keep pests at bay and at the least are pleasant to work around.  For the most part, the more aromatic the herb, the more unappealing they are to pests. There is also diatomaceous earth.  Diatomaceous earth is the skeletal remains of tiny prehistoric sea creatures called diatoms.  The shells of these single celled fossils are broken down during processing into needle like silica particles that penetrate the bodies of bugs on contact. Since bugs are held together by their exoskeleton, their insides gradually ooze out and they die of dehydration. If you dust after a light rain or mix the powder into a spray will help to keep the product where you put it.  NOTE: Although it's considered safe for people and animals, it does irritate some people's lungs.  This product not only harms pests in your garden, it also kills beneficial insects and earthworms.  Be sure to buy diatomaceous earth specifically for garden use and not the ones made for cleaning swimming pools. Well, that's it for this installment. I hope you have decided to give some of these ideas a try in your garden. Remember you can E-mail any questions you might have to kntjones@mindspring.com.  And here's a quote from Ralph Waldo Emerson.  ‘The earth laughs in flowers.’ So I guess since the earth laughs in flowers, everyone preparing the soil for their gardens are tickling the earth.  Just a thought. Keep your thumbs green and your gardens laughing.By