ag (1109) - Lettuce: pest triangles

we had a look at these pest triangle thingies.

the pest or disease would be in the middle of the triangle, the host at the top, the source on the bottom left, and the preferred environment of the pest on the right

using these, we deduced things which are all in written in my book, things like coz sowthistle weeds host sowthistle aphids, clearing the weeds can reduce aphid popultions.

then we had a look at the resistance of pests.

it works like this

an insecticide is sprayed, not all pests are killed.. and the survivors breed and pass on that trait.. after a while, they will be immune.

to reduce this, one could alternate between chemicals, or use IPM so its not always necessary to use chemicals.

spraying more often or more concentrated could work better though.

but things that oculd lead to higher speed of development of resistance include:
- spraying many times in a season
- underspraying or overspraying
- not rotating chemmicals
- or too high/low concentration of chemical