Some species of cactus with a milky sap (and all Euphorbia species) have a group of chemicals known as "diterpene esters" which have insecticidal properties. However, these chemicals are dangerous...
Many pesticides use chemicals that accumulate in the soil and the ground water. At a point in the future they could reach dangerous levels and we may not be aware of the impact of effects they could...
Generally, lizards aren't pests and you shouldn't try to kill them. Honestly, they eat all manner of icky bugs. Killing the insects will reduce the lizard population.
the pesticides kill pests, like worms and mice, which compete with the plants for some things from the soil like nutrients, and they also eat the plant directly, killing it. if some of the plants...