Does the swallowtail butterfly kill bad insects?
Butterflies don't kill anything. If they are eaten, they don't taste good and can make them sick, but it isn't likely to kill anything.
Yes pesticides are some what bad because of what they do, they kill insects. They also go threw the ground and eventually end in water making pollution... Some of the insects that the pesticides kill are actually not going to hurt the plants that the pesticides are on in the first place. that means pesticides kill and pollute, does that sound very good. Pesticides are made from chemicals, bad ones at that and poison's in…
Well they try and kill the pest insects that damage their crops but unfortunately the insecticide sprays they use actually kill all insects which, while perhaps OK for the farmer is very bad for the ecology and biodiversity of the planet.....also we end up eating some of these chemicals and as they are poisons it can not really be good for us.
Bad? No. Dangerous? Some are. Spiders are not as harmful to humans as many insects. They tend not to land on, or spoil, food. They don't spread the diseases that many insects and other animals carry. In fact, most spiders are beneficial to us - because they eat insects which are harmful to us. As to "bad" - no, it is people who are "bad".
Pesticides are poisons: they kill the particular pest that they are intended to kill, but then they seep into the soil or into water systems, where they can kill other needed insects, can be ingested by fish or other aquatic life, and from there be ingested by birds or larger animals. A buildup of residual pesticides in a given area can do tremendous damage to the entire ecosystem.
Can you mix insecticide with weed killer for a one-step application instead of mixing and applying them separately?
That's a really, really bad idea. If you do that you could kill the plants that you are trying to get the pesky insects off of. Insecticide is used ONLY for killing insects that damage your plants. Herbicide (or weed killer) is used to kill plants (a.k.a weeds), and is often a non-selective herbicide which means if you're not careful, you could also kill your plants too.
Pesticides are designed to kill pests. If a plant is a pest (weed) a pesticide intended to control it will kill the plant. Pesticides that are designed to kill insects and beetles that damage crops nevertheless may leave a residue of the poison on the plant itself. This may not hurt the plant but may be hazardous to other animals that eat the plant. This is why such food should be washed before being eaten