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Lily Beetle by Ian Wise

(Update 2019)

The scarlet lily leaf beetle Lilioceris lilii, was first found in Manitoba in Portage la Prairie in 1997, and spread to Winnipeg in 2004. It has most recently been found in Brandon. Its distribution is aided by the commercial movement of infested potted lily plants.

A parasitic wasp is being tested to determine if it can reduce the presence of the lily beetle. It was just found to be able to overwinter in Manitoba, which opens up the opportunity to disburse the wasp into areas infested by the beetle.

In the interim, lily growers are advised to control the beetle by observing areas where lilies grew the previous year, and then killing the beetles as they emerge. Remove any leaf litter once snow melts from these areas to hasten beetle emergence.

Larvae on plants can be controlled safely with spray applications of insecticides that contain pyrethrum. There are a number of products with pyrethrum that are available at Home and Garden shops. Use a sprayer that enables the spraying of the under surface of the leaves where the larvae feed. Direct spray contact of the larvae is needed for pyrethrum products to be effective.

 

 

Life Cycle of the Red Lily Beetle (Lilioceris lilli)

(With suggested Controls)

  • Over wintering adult beetles emerge in early spring from the surrounding soil to mate and lay 200 to 400 eggs on the underside of the leaves of the lily plant.

  1. Handpick the adult beetles (6-8 mm ¼ inch in length) as soon as they appear on the emerging lilies.
  2. Spray the adults with any pyrethrum based (0.5%) insecticide or any other registered pesticide. Rotenone may also be effective.
  3. Destroy the egg cases on the underside of the leaves.  Eggs are in yellow/orange clusters or in irregular rows. The eggs are quite small, approximately 1 mm.
  • Eggs usually hatch in about 7-10 days.

 Photo by: Paul Mabbott

  • Emerging larvae will begin feeding on the underside of the leaves and then move to the top. This stage lasts for about 16-24 days. They will cover themselves with their own feces to discourage predators.

 

  1. Remove the larvae.  Can be very messy.  Use rubber gloves.
  2. Dust or spray with Rotenone or any pyrethrum based pesticide at 5-7 day intervals.
  • Larvae drop to the ground and pupate for about 20-25 days.  Pupae cases are dark brown or black in color and very hard to find in the soil.
  • Emerging adults climb plants and feed until fall but do not normally mate or lay eggs until spring,
  1. Handpick the adult beetles.
  2. Spray the adults with any pyrethrum based (0.5%) insecticide or any other registered pesticide. Rotenone may also be effective.
  • Adults over winter in the surrounding soil or under plant debris.  Some adults may survive over two seasons.  Stir up the surrounding soil or the mulch in early spring and kill any emerging beetles before they have a chance to lay their eggs.


Note: The lily beetle has no known natural enemies in Canada. It is up to each gardener to check their lily plantings at least weekly for signs of the beetle. Because the beetles are strong fliers and can move around the neighborhood, inform your neighbors and help them to control this pest. The beetles have been reported  in most parts of Winnipeg as well in various provincial locations.

 

Note: All information in this article has been obtained from various sources on the Internet.  Use your own discretion in controlling beetles on your property and use only the methods with which you are comfortable with.  All organic or chemical pesticides should be handled as directed by the manufacturer.  There are no pesticides specifically registered for use on lily beetles in Canada.