Ok, I have been writing about the benefits of sustainable gardening practices and the importance of non-reliance on chemical control methods to help curtail excessive pest pressure in the home garden for a few years now. And from time to time I manage to document some interesting little strategies to encourage beneficial insects to feed in our patch and also the benefits of biocontrol and how exactly they predate on some of our most common pests, like aphids, mealy bug and scale insects. But beneficial insects have been playing a huge role in keeping some pests at bay for over 100 years now, especially in large scale farming practices worldwide. Back in 1888 in California, the citrus industry was almost wiped out by the cottony cushion scale infestation, the pest pressure became so well established that year, that the citrus trees appeared white like snow from a distance. Specialists in the field soon realised that the cushiony scale was not a threat to the Australian citrus industry, so a trial began in importing hundreds of thousands of our native ladybird larvae Rodolia cardinalis to California for initial biocontrol. Within 12 months the Australian insects had helped to control the entire cottony cushion scale outbreak in the Californian citrus industry which helped prevent the entire industry from collapsing. See Image below: Rodolia cardinalis and her larvae feasting on cottony cushion scale- Icerya purchasi.
In Australia, we have many pests that can be controlled by biocontrol agents. For example, the Silverleaf whitefly- Bemisia tabaci, has become well established as a major pest which causes a reduced yield and quantity in the cotton and sweet potato crops. This pest has the ability to introduce viruses too. One solution is a tiny yellow parasitic wasp- Eretmocerus hayati, which lays its eggs directly under the whitefly larvae, hatches and then penetrates inside the hosts larvae, which as a result reduces the pest pressure naturally, meaning less need for chemical control. Interestingly over 90% of Australian cotton these days is genetically modified with (Bt) technology, Bacillus thuringiensis, which is a natural bacterium, and when ingested by caterpillars such as Helicoverpa armigera, (Cotton Bollworm), poisons them. Using the genetically modified cotton strains has reduced the pesticide usage in the industry by 92%, according to the ‘Cotton Australia’- fact sheets. Now, this coupled with the biocontrol using the parasitic wasp- Eretmocerus hayati, for the Silverleaf whitefly pest has got to be a good thing for the industry and the environment indeed. I am passionate about sustainability as many of you know and I am fortunate to meet some fascinating inspiring role models who live and breathe their passion with their chosen career path, and a chance meeting last month with Zen Kynigos, an operations manager for a leading commercial biocontrol farming enterprise, called- ‘Bugs for Bugs’, was exciting indeed. The commercial enterprise grows biocontrol insects such as the parasitic wasp- Eretmocerus hayati, which I mentioned above, and array of commercial quantities of biocontrol agents like predatory mites and lady beetles to only name a few, but I really resonate with their mission statement. “Our mission is to help Australian growers achieve best practice pest management with minimal pesticides”. For more information on commercially available biocontrol solutions, visit online at: https://bugsforbugs.com.au
