Naked Science Forum
Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: kierae0608 on 21/07/2011 13:01:52
-
I recently heard that aphids are immune to pesticides, Is this true or are where they pulling my leg. ?
-
The answer is 'yes', someone is pulling your leg.
There are many insecticides which will kill aphids. The most common in use today are the contact insecticides. There is a desire to get away from the systemic insecticide which were the most common in use up until a few years ago. It is thought that these systemic insecticides may have been responsible, in part, to the decline in bees, butterflies and other harmless, desireable and essential insect life.
The greenfly & blackfly can be easily controlled with contact insecticides (do please remember to follow the manufacturers instructions and NEVER use them while bees are active).
The real problem is the whitefly. Because of their short and fast lifecycle, they can be a real pain in the arse garden. They tend to appear in great numbers to feed on the sap in the young growing shoots of plants and very quickly lay eggs. The eggs are not affected by insecticides and will hatch within a few days. This makes contact insecticides pretty much useless in the fight against the whitefly.
Now I don't wish to plug or advertise any product in particular, but Bayer Provado™, Ultimate Bug Killer™ is a systemic insecticide which will help in the control of this pest. Other brands available include
Scotts™, BugClear Ultra™ and Westland™, Plant Rescue Bug Killer™. These contain thiacloprid, thiamethoxam or acetamiprid.
Whitefly bring a secondary problem, in that they exude a sugar rich poo which is highly attractive to the fungus known to horticulturalists as 'Sooty Mold'.
In the greenhouse, the use of stick yellow cards can be the best bet.
As to a natural defense against whitefly, the Ladybird and Lacewing are good allies as is the predatory wasp Encarsia.
-
No one is pulling your leg, but this resistance will be a response to a pesticide that has been used for several generations in the insect. Also there are some products out there that will kill them, and most likely anything else down wind.
I found a good technique for getting at aphids is to use a samll amount of biological washing up liquid and spray that onto them. Aphids breath through their skin so by blocking the respiratory system you kill them and washing up liquid does a pretty good job.
Some species of aphid will all swarm and gather in one place in large numbers, this is normal behavior for social insects. You get a bag and put it over the bunch of insects and snip off then branch/stem they are attached to.
By using a combination of both techniques you can really make an impact. In some area's people may have noticed, every year a certain insect seems to be more successful then others and more noticeable then others? last year here for example it was horse flies, the year before that Daddy Long Legs, or Crane Flies, this year it's just flies. So if you happen to live in an area with an aphid explosion it's tough luck!
-
...... this resistance will be a response to a pesticide that has been used for several generations in the insect.
This true, of course, and is one of the reasons the products on the shelf of your garden centre change over time. But there are plenty of insecticides effective against aphids.
-
.... there are plenty of insecticides effective against aphids.
Do these insecticides target Aphids only?
-
No, I don't think any manufacturer has marketed one specifically for use against aphids, they tend to be effective against a range of insects, such as Sawfly, Thrips and Mealy bug etc.