|
In my new home, I am surrounded by Black Walnut
trees so I'm busy collecting
information on the
allelopathic
toxin called Juglone and which plants
are most susceptible to it. If
anyone has any experience
with this frustrating problem, please share! Much of the
information I've collected so far traces back to only a few
original sources so any first hand information would be
welcomed before I kill too many plants!
Evelyn
Lily Beetle
Not
an easy pest to control if you love to grow Lilies.
Here's the information you need to develop a battle plan.
 This imported pest
attacks and lays its eggs on, Lillium and Fritillaria species. First discovered in North America in 1992, (most likely imported in a shipment of lily bulbs from Europe), it has since spread throughout the northeast. They are strong fliers so can seek out their target, but are
also moved around on host plants - i.e. your new lily purchase. Both larvae and adults cause great harm to their host plant by weakening them to the point of death. Unlike most other garden pests the lily beetle has no natural predator on this continent, which is how they have been so successful in their
advancing march through lily beds everywhere.
Identification:
Adult Beetles are easy to spot - bright red, squarish, and about 1/2" in length. The larvae
 are slug-like with swollen bodies and black heads, and look just like a little slimy mass of fresh bird droppings, but watch for a few seconds and you'll see it wiggle and move - definitely not bird droppings. The fecal part isn't so off-base though, since the larvae cover themselves with their own fecal matter to deter predators.
Life Cycle:
Adults over-winter in the soil surface or under debris to emerge in spring (right in sync with the new lily foliage) and immediately feed and mate. Soon after mating, females lay brownish orange eggs in irregular lines on the undersides of lily foliage that hatch within 4-8 days. This more or less brings us to early June when you'll see the young larvae initially feeding on the undersides of the foliage but later on the upper surfaces and the buds. The larval feeding period is the most destructive and lasts for 16-24 days. They then drop to the soil to pupate and new adults emerge 16-22 days later (which brings us to more or less early August) and the new adults can be seen feeding throughout the rest of the growing season. These are the ones that will tuck in over-winter just under the soil surface and begin the cycle again in early spring. Each female beetle produces 250-450 eggs.
Management:
If you focus on the life cycle, it's easy to see when you can be most effective in controlling this devastating pest. Cultivate the soil surface in late fall to search for new adults bedding down for winter. In early spring just as lily foliage is emerging, the beetles will too - be vigilant for a couple of weeks in hunting down the over-wintered adults you missed in your fall hunt, before they have a chance to mate. Assume that you missed a few, and in a week or two start another search and destroy mission each day, this time looking for eggs and newly hatched larvae. Again, assume that you missed some and in early August watch for new adults.
As with any garden pest that has the ability to over-winter, once you've got them, you've got them for good, and you'll have to be on
patrol each year. Controlling any garden pest effectively is possible
though, when you focus on its life cycle. With a watchful eye and a gloved hand you'll be able to keep
populations down to an acceptable level.
If you don't have lily beetle in your garden, don't be smug - that can change with just one new un-inspected purchase. Someone today gave me a tip that is so obvious I'm embarrassed I didn't think of it! When purchasing new lily bulbs, or accepting a gift from a gardening neighbour, rinse them thoroughly before they even get near your garden. Remember, you're looking for bright red adults or slug-like larvae in the soil - not eggs, so they should easily rinse away if present. In the case of potted bulbs already growing, rinse them nevertheless - washing away all soil in among the roots in room temperature water before planting, and also inspect stems and foliage for eggs. Even just one beetle that makes it into your beds can begin the ravaging cycle.
by Evelyn Wolf, Garden Possabilities Bookstore
|
