I live in southern California, and it's almost winter here. I have 3 citrus trees, and 1 mango tree. My citrus trees almost always get attacked by spidermites. What time of the year would be the best time to spray my trees for pests? I had planned on using a chili/neem oil mix to spray. Can this be done anytime of the year?
Spray for spidermites as soon as you see them - the formula you're using won't harm the tree even if it's in production at the time, but it won't work unless you hit the mites.
I'd go systemic every 7 days for a month from the first time you see a mite - that will get any stragglers or hatchlings and should keep the trees mite-free.
Neem oil has the added benefit of being effective against scales as well, which are the bane of any citrus-grower's existence.