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What a long, strange spring it's been. Warm early, then cool and moist. In spite of my efforts at frost protection, I've only got one fruit on my big apricot tree. The apples sure look good, though, as do the roses and the brooms — blossoms from here to eternity. Credit winter and spring moisture for that gift, which like most gifts from nature, is not as simple as all that.

I've gotten a lot of calls in the last weeks from folks whose mulberry trees are losing leaves at a prodigious rate. Typically, these leaves will have some amount of black spotting on the leaf blade, and there may be blackened, shriveled tissue at the base of the leaf or of the small shoot. If you've ever seen the effects of fire blight on a pear tree, it looks a lot like that.

Not knowing exactly what we were dealing with, I sent samples down to the plant pathology lab at New Mexico State University in Las Cruces. The answer: phomopsis leaf blight. This fungal disease affects many different species; it showed up late last summer on my lilac shrub.

The good news is that it is a weak pathogen, and generally attacks plant tissue weakened by some stress. In consultation with some of my colleagues here in town, we concluded that late frost, or near-frost, temperatures probably caught developing leaves at a particularly vulnerable stage, setting the stage for the phomopsis to move in.

The trees will lose some leaves, but now that temperatures and humidity are returning to a more normal spring condition (that would by hot, dry and windy, in case you hadn't noticed), the problem should go away. The trees will put on new growth, and should be fine.

Other seasonal issues popping up include cottonwood leaf beetles. The adults are small, slender beetles. Their shells are a yellowish tan, with long black spots. The larva, which is the more destructive stage, is mostly black, with some white spotting on the edges of the body.

Both adults and larva feed on cottonwood leaves, leaving behind the veins in a pattern known as "skeletonizing." There are two generations a year, and we are witnessing the first of those.

There is a rule of thumb that treatment is not necessary if the damage from the first generation is less than 20 percent defoliation, and 40 percent defoliation for the second generation. In many cases, no treatment would be warranted.

If treatment were called for and the larvae were still young, one could use Bacillus thurengiensis (either the "San Diego" or "tenebrionis" variety), spinosad (a fungally-derived insecticide), or a neem product containing azadirachtin. More mature larvae and adults would likely need a treatment with carbaryl or acephate, both fairly wide-spectrum insecticides.

Of course, the real difficulty comes in trying to treat a large tree with a sprayed-on product. Injection of insecticide directly into the trunk is an option available from licensed pest-control applicators, but the act of injecting the trees may do more long-term damage than the beetles will.

Think of it this way: Plants, insects and diseases have been co-evolving for millions of years. Plants can take a fair amount of damage before they are seriously threatened. Just like humans, not every head cold or bee sting is a life-and-death situation, and over-reacting often takes a small problem into the realm of serious problem.

Have some faith in the strength of our leaved friends — they may be tougher than you think.