grasswhacker:

Well, what is it? I mean, what are the component chemicals? Is it a combination spray, with several components? Wettable powder or liquid? Unless it is something like BT, which declines in effectiveness over time, most chemicals do not seriously degrade with age.

And what is the job you have in mind for it? What kind of fruit trees do you have, and what are the insects/diseases that seem to be troubling them?.

With fruit trees, it is best to determine what the problems are and try to match the treatments to the problems rather than spray with whatever is at hand and hope it cures what may or may not come along.

Don Yellman, Great Falls, VA

The label says "Protects fruit and trees 5 ways - insecticide, fungicide, aphicide, miticide, and scalicide". It is a concentrated liquid spray. I don't know how carefully it was stored.

Forgot to mention. It will be used for apple trees.

Uuugh, there's no way in he!! I'd spray something that probably contains that many different products. Sounds fishy (and potentially dangerous) to me.

grasswacker:

There are still a lot of useful facts that you could supply, such as: Are these newly-planted trees or older trees that have borne fruit in the past? Theoretically, the answers should be much shorter than the questions, but it always works out other way around as we engage in guesswork based on limited information.

If these are mature, producing trees, you will have to begin spraying soon after petal fall, even before your first thinning. (Did I mention thinning?) One of the the worst insect pests of apples, the plum curculio, which you likely have wherever you are in Maryland, will attack the young fruits just as soon as they set. You have to have a cover spray on there to stop them. And, depending on the level of PC pressure you have, which will be followed by codling moth and possibly others, you may have to renew your spray every week to ten days throughout the growing season. That is, unless you bag your apples which is another subject.

I am not quite as discriminating as the fruitgirl, and would probably use the spray you have purchased until it is gone. You still did not mention the chemical components of the concentrate, which are surely listed on the label, but lets just asssume they are the usual suspects such as Sevin, Malathion, Methoxychlor, Captan and one other which shall remain unknown. One of the characteristics of "combination" fruit tree sprays is that they contain many different components, but are weak in all of them. And for the targeted insect or disease, only one of them may be helpful.

Nevertheless, if your insect pressures are low, and you don't encounter any diseases such as scab, cedar apple rust or fireblight, you may be able to get by with your vintage combination spray. You certainly won't do any harm with it. But get at it the day after petal fall, and keep an eye on the apples every day thereafter to see if anything is bothering them. When you thin, take off any little fruits that have the slightest scar or mark on them, leaving behind only the perfect little fruits to grow up.

Don Yellman, Great Falls, VA