Fighting pests with… pests? Getting creative with Integrated Pest Management

Pests are inevitable in any garden. For Melbourne Gardens however, a proximity to the city and large numbers of visitors creates something of a paradise for pests. Invasive species are one of the most significant threats to the Garden’s biodiversity and precious living collections so effective pest management is crucial. 

Dealing with pests can be tricky, especially while striving for sustainability and avoiding harsh chemical pesticides. As part of an Integrated Pest Management (IPM) strategy, the Garden’s staff have adopted some creative and natural methods. Their IPM combines biological, cultural and chemical processes to control pests, resorting to pesticides only when pests are unable to be controlled with natural methods.

One novel technique the nursery team at Melbourne Gardens has adopted is to use bugs to fight bugs! After a mealybug outbreak on the succulents destined for the Arid Garden collection, the team decided to unleash a consignment of ladybug larvae (Cryptolaemus) to combat the outbreak. Biological options like these (cute?) fluffy looking larvae can be an effective, natural way to manage these issues. In addition to predatory insects, the nursery employs the help of some other local critters. “We have tree frogs in the nursery which will pick on slugs and other insects. We also have carnivorous birds which will check the plants for scale insects” says nursery horticulturist, Chris Jenek. 

Another strategy the team uses is to alter the temperature of the plants’ environment in order to combat fungal pests. “If we have a fungal problem we can increase or decrease temperature and humidity to combat that. I can't recall the last time we actually sprayed plants in the nursery” says Chris. The diversity of plants held in the nursery also offers an inherent safeguard against pests. “This nursery is unique because we don’t have thousands of the same variety of plant, so even if we have a problem it won’t spread because every plant is different. It won’t jump from one to the next.'' 

Outside of the nursery, predatory nematodes have been deployed across the wider environment of Melbourne Gardens. These creepy-looking critters inhabit soil and are the most abundant multicellular animals on earth. They attack soft-bodied, slow-moving pests that prey on flora while sparing precious earthworms and plants. While somewhat out-of-the-box, these sustainable methods of pest control aren’t applicable only in large gardens. Trying out these techniques at home could help you transform your backyard into a pest-free zone without reaching for pesticides!

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