I have a smallish garden. With several sections, unconnected by soil. In one section I am growing trees that are being dosed with systemic imidacloprid. Near by, but in pots, I am growing some herbs that currently use no insecticide.
To deal with aphids I would like to buy and release ladybugs. But I am afraid they may be poisoned by the nearby trees.
Should I be concerned about this or take a different approach to clearing the aphids?
It's a complicated picture, because the ladybug population is affected differently depending on how often you're using imidaproclid and how soon after application the ladybugs are around. In general though, the population of ladybugs in areas untreated with any type of insecticide is higher than in areas where insecticide has been used. The link here details some experiments on the impact of various pesticides on the ladybug population at different times, if you're sufficiently interested to pick your way through it:
From a logical point of view, it would seem a waste of money to buy in ladybugs which cannot be guaranteed to remain only on your herbs, but may well migrate to the insecticide soaked trees or anything else nearby. If you live somewhere Neem based treatments are available, it's probably worth considering those as an alternative for use on your herbs instead.
Oh I agree with Bamboo. Why are you using this pesticide? This stuff is highly toxic to bees. If Lady bugs eat the aphids that suck on thin skinned plant parts of plants that are full of systemic pesticide, yeah, it'll kill 'em. But not to worry. When one releases Lady Bugs on their property not a one will stay! All your neighbors will enjoy their labors, not you. Lady Bugs are programmed to LEAVE home. Hope you haven't purchased them yet. Grins! You could go to your neighbors to release the Lady Bugs!!
Pesticides should be absolute, absolute last option for managing a garden. In fact, pesticides/herbicides are just a bandaid on a problem, never a solution and if not used expertly will ALWAYS cause bigger problems in the garden. As a licensed pesticide operator for 2 decades, I have RARELY used pesticides. If these chemicals made landscape maintenance any easier, more money...I, sigh, probably would have used these chemicals. But pesticides never made sense for solving any problem in the landscape. Being professionally involved with landscapes/gardens over 3 decades I've used some glyphosate, Round-up, Neem, garden grade soap...that is it. And I was certified, educated, experienced. Why this stuff is available to anyone has always been a huge conundrum for me...
Depending on what plants have aphids right now, how big an infestation, you can easily use strong streams of water to knock aphids off plants, next strongest solution would be a soapy water solution using non-caustic soap and finally, NEEM would be the strongest pesticide you should ever have to use on aphids. Use at night to ensure bees are not active. Only takes one bee to take pesticide back to hive and entire hive is poisoned.
Send a bit more information and pictures! Nothing should ever be done without absolute certain ID of target!! Bees are in big trouble and almost all of life is dependent on bees. A few months without bees and even us humans will be in major trouble.
