Q: We have a mimosa tree in our front yard. We noticed this year several larvae rained down from the tree onto a table. After searching around the tree it appears the bean pods are infected with these larvae feeding on the seeds inside the pods. It does appear there are some tiny black ants feeding on the larvae but we’re not sure. We don’t want to use chemicals that might kill more beneficial insects that feed yearly on the flowers. What are these larvae and how do we prevent this in the future? – J.R., Albuquerque.
A. I have no idea what critter these larvae will become, but here’s what I believe is happening. Earlier this year you had some sort of adult insects lay eggs throughout the mimosa, probably just at the spot where the flowers extended from the stems. As the eggs hatched, they burrowed into the young bean (seed) pod and have been feeding and growing well all summer long.
These larvae are now entering the next stage in their lives. They are exiting the mimosa seed pod and your table got in the way.
The ones that have made it to the ground are burrowing into the soil, where they will winter over, going through a couple of more stages, before becoming adults.
Next year, they will come up out of the soil and go on to continue their lives. They’ll mate, lay more eggs, the eggs hatch, feed in the seed pods, fall to the earth, pupate and do it all over again. It’s their cycle of life.
I don’t know if they’ll be a beetle, a moth or even some type of butterfly in their adulthood. To help keep the population under control, I suggest you cut off as many of the seed pods as you possibly can and dispose of the pods. It could be a very daunting chore, but the more of the seed pods you eliminate, the fewer of next year’s crop will infect the mimosa seed pods.
But again, I don’t know if these critters are going to become what you call a beneficial or not.
Next year, just before the mimosa comes into bloom, I’d consider spraying the tree with a summer weight horticultural oil to perhaps stop any eggs that hatch from being able to affect the seed pods.
The blooms should still be able to bloom and feed your beneficials without harming them. But it will need to be a well-timed spraying. Spraying the blooms when they are open could disrupt them and the bloom could be distorted.
But for now, cut off and dispose of as many of the seed pods as you can.
Q: The pots I have filled with my plantings of summer annuals are blooming like gangbusters. I don’t want to pull them up to make way for the planting of pansies yet. How long can I wait until I change over to my winter pots? – K.C., Albuquerque
A: It was so hot and so dry for months this year my annual plantings are “blooming like gangbusters” now, too. I don’t have the heart to pull them up yet.
The daylight is shortening markedly and the temperatures have cooled delightfully, so that’s why the summer plantings are doing so well. I’m noticing a bit of finishing this last week and in two weeks, by mid-October, I’ll bite the bullet and pull up this year’s annuals to plant my winter crop of pansies.
Since the weather is cooling so marvelously, I’m not going to wait much longer than that to get the pansies settled. I’ll give the soil a good turn and consider adding some bulb food (higher in phosphorus) to the pots and get the pansies planted.
If all goes well, there’ll be color in the pots for the balance of the winter months. It’s tough when you have plants that are still giving you their all, but soon, if not already, they’ll show signs of being finished, so you don’t have to feel bad about getting your next display started.
Happy Diggin’ In!
Tracey Fitzgibbon is a certified nurseryman. Send garden-related questions to Digging In, Albuquerque Journal, 7777 Jefferson NE, Albuquerque, NM, 87109, or to firstname.lastname@example.org.