Biological Warfare: Treatment for Root Weevils
Do you have any leaves that look like the ones in these pictures? This kind of damage is produced by adult root weevils. Root weevil larvae overwinter in the soil and can do serious damage to root systems. Rhodos, Camellias, Laurels, Bergenia, Heuchera, Primula and a host of other plants are all susceptible to weevil damage.
Stratiolaelaps: Treatment for Vine Weevils
Applied Bionomics is a local company that is a world leader in the development and production of biological pest controls and they have been testing Stratiolaelaps scimitus (formerly Hypoaspis miles) with impressive results. Stratiolaelaps are microscopic organisms that seek out and destroy root weevil larvae, thus disrupting the cycle so there are fewer adults feeding during the growing season. It takes a year or so for the results to show, but in test areas the weevils have all but disappeared, as evidenced by the healthy foliage on plants that were previously badly eaten. It also appears to be effective against cutworms and other grub producing species as well as flower thrips.
Stratiolaelaps can be applied at any time of year and needs to be used just once as it will establish in the garden once introduced. It comes mixed with sawdust and all you have to do is shake a tablespoon or so around plants that show signs of weevil damage. For a small garden or one with only a few affected plants there is a half litre bag and for a larger garden there is a 1 litre bag. Give us a call and we will order you some in for you, usually for pickup on Thursday or Friday.