Ripper of a book this one. Jackie is the potion master - and she explains what the mode of action is, how to make the potions, and how to work out what to try, as well as giving explicit recipes for specific pest problems.
It's only a little book - mine was $15, although that was years ago. I bet it's still in print though (or something similar by Jackie will be).
Jess was asking about caterpillars on cabbage family. Here is what Jackie has to say.
Under caterpillars in the index she lists cabbage moth, cabbage white butterfly, codling moths (apples), Dipel, kurrajong leaf roller, predators of (caterpillars), and trap.
She talks about encouraging predatory wasps, assasin bugs, mantids, centipedes, dragonflies, ichneumons, scorpion flies and spiders (a good reason not to spray biocides if you can get away with it? SJP). Elsewhere she talks about what to plant and what habitat to provide to do this. She also says that lacewings eat caterpillar eggs and hoverflies may eat very tiny baby caterpillars. There is also, apparently a natural caterpillar virus.
Jackie says that in a diverse garden the natural predators may be enough to control the caterpillars (but give them a couple of weeks to notice the new food source). Recommendations to preserve this natural predation include to squish the caterpillars and eggs on the leaves, or use Dipel. Other controls recommended include:
* eggshells in beds (to make the butterflies seek less crowded accommodation SJP)
* companion plant with smelly things - eg lavendar round edges of beds ( and especially dill SJP)
* Interplant to stop caterpillars migrating between plants (and to disguise the round outline of brassicaceous leaves by which it's thought that the moths/ butterflys may partially recognise their host plants SJP)
She says make sure you spray or dust under leaves as well, cos that's where the caterpillars and eggs mostly are. Potions etc recommended are:
* flour (poisons caterpillar tummies within 3-4 days)
* clay spray
* bug juice (made of squished caterpillars - nasty! but effective?)
* white pepper spray (will dehydrate/ kill them and make them easy prey for birds)
* powdered rock phosphate (same effect)
* wormwood spray
* derris dust or spray
place a small, three sided box at the base of plants, sbout 10mm high. Place a scatter of lime or wood ash inside - the caterpillars should shelter in there during the day.
See? She's the wizard. I love Jackie French books. The best.