Growing the Desert Garden

Welcome to the Desert Garden, with garden coach Tyler Storey, where we talk about everything having to do with gardening and landscaping in the Desert Southwest. From composting to Cercidium and agaves to arugula — we'll cover everything you want to know to grow your own beautiful Desert Garden.

Tuesday, May 6, 2008

Orchard Forensics

Plum leaf damage © Tyler StoreySomething has damaged a number of leaves on one area of the the Santa Rosa plum tree; they're ragged around the edges and look a little tattered.

Wind damage? It's been windy the last few days, so it could be that, except there is nothing for the leaves to have been tattered against, and most of the damage is to the edges of the leaves. Wind damage would manifest on the entire leaf. Not wind damage.

Maybe caterpillars. The edges definitely look like little bites have been taken out of them, just the kind of nibbles that little caterpillars take. The problem is the damage is spread over a number of leaves on different twigs; caterpillars are mobile, but not quite that mobile, so it would have to be a lot of caterpillars. I would probably have noticed a lot of caterpillars, or at least their droppings, and this is fresh damage so some of them would still be around. Not caterpillars.

Leafcutter bees? Most leafcutter bees cut large ovals out of the edges of leaves, resulting in a very distinct shape. Nope, not leafcutter bees; dismiss that without another thought.

How about grasshoppers? Grasshoppers chew in a very ragged pattern, and that fits. Grasshoppers jump from one leaf to the next, so that solves the problem of damage on multiple leaves. Most grasshoppers are large and their bites are correspondingly large; these are pretty small. Except, it's late Spring and that's grasshopper nymph season, and grasshopper nymphs take little bites, just like these. Problem solved: it's grasshopper damage.

A magnificent example of reasoning and analysis. Also entirely wrong.

Five seconds after I reached my carefully thought out conclusion, a little tiny bee landed on a plum leaf right in front of me, cut out a tiny little ragged piece of leaf, and flew on her merry way. I forgot about this one: I've seen her before, but we've never been formally introduced.

The damage to the plum is minor and we don't want to harm pollinators, so I'll let her do her thing unmolested. There's no effective control available anyway, so that was an easy call to make.


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