by Andreas Neuman
Published on January 11, 2019
This article was initially published on Freshfruitportal.com.
According to some studies, the global market for biological control agents within agriculture is predicted to grow from its 2015 level of USD $1.6 billion to USD $3.5 billion by 2021. Increased awareness of its effectiveness along with a desire to reduce chemical usage is leading to a 13% annual growth rate, but there still are lots of growers who have not yet had an opportunity to be introduced to the discipline of biocontrol. To that end, we hope this first article in a series exploring the topic is informative.
There are nearly one million known species of insects, and their place in history is not a glorified one. They have been the culprit of numerous outbreaks of disease and famine, destroying humans’ hard-earned agriculture production with a seeming malice. However, only a relatively small percentage of insects pose a threat to crops. In fact, there are many useful or “beneficial” insects and mites who provide farmers around the world a valuable service preying and parasitizing pest population. These beneficials fall under two broad categories, predators such as the ladybug which hunts prey insects, and parasites such as some types of wasps that lay their eggs inside host insects, eventually killing them. Within both of these categories, there are generalists that target a wider array of prey or hosts, and specialists which narrow their target lists to a small number.
From Ancient Egypt to modern farms
Biocontrol (or “biological control”) is a proven method within the field of Integrated Pest Management (IPM) where pest populations are controlled by using their natural enemies. There are three basic applied biocontrol strategies; 1) Classical, which imports natural enemies from outside the local area, 2) Conservation, which seeks to enhance the effectiveness of existing beneficials, and 3) Augmentation, which boosts existing or re-integrates eliminated beneficial populations.
Biocontrol is not a new concept. Ancient Egyptians used domestic cats to control the rodent populations that threatened their grain supplies, ancient Chinese citrus growers moved predaceous ant nests into their citrus fields and even built bamboo bridges so ants could more easily move from tree to tree, and Yemeni farmers traveled to North Africa to bring back predacious ant colonies for their local date groves.
Even with the advent of powerful chemical pesticides, biocontrol has some distinct advantages – even outside of organic farms. First, and perhaps the best-known benefit, is the reduction in environmental, legal and public safety risks as biocontrol minimizes direct chemical exposure, groundwater contamination and the rise of resistant strains of insects. Second, biocontrol plans can be more selective than broad-spectrum chemicals, leaving intact other beneficial populations such as predatory mites which may be stealthily controlling outbreaks. While difficult to precisely quantify, the reduction of future outbreaks can clearly have tangible bottom-line results as treatment costs and losses are reduced. This can have positive bottom line results in the medium to long-term as treatment costs and loss due to future outbreaks may be reduced. Third, the beneficials can crawl high up into the canopy of trees and to the underside of leaves, areas where chemicals have a difficult time reaching and where some pests such as melon or cotton aphids tend to reside.
Implementing biocontrol is easier than you may think
One common complaint about biocontrol is that it takes education and training to properly design and implement biocontrol as part of an integrated pest management plan. While this is true, there a growing number of experts in the field who are capable of prescribing highly customized and, most importantly, cost-effective plans. One of the first criteria they will assess is, what are the unique threshold levels for the grower? In simple terms, how much damage is “acceptable” before leaving pest populations untreated results in costs greater than the cost of treating it? This “acceptable” level of economic damage is directly correlated to the density of a pest population and sets an initial target for population control. Once an entomologist understands the grower’s economic constraints, they can start building a comprehensive preventative and curative pest management plan tailored for local threats.
In addition to the growing body of knowledge driving the growth of biocontrol adoption around the world, advances in distribution technology are dramatically improving the precision at which control agents are released as well as opening up new crop types to biocontrol. For example, drones equipped with specialized hardware designed to release beneficials can compete on cost with manual labor – especially in tight labor markets such as California – and they also ensure a more even distribution and can reach the tops of canopies that are too tall for traditional (hand) applications.
Over the course of a short series of upcoming articles, we will take a little deeper dive into certain aspects of biocontrol that we feel may be of particular interest to you. We’d love to hear from you – what would you like to learn about in future articles? Do you have any comments or questions about what you’ve read so far? Let us know – we read all the comments.
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A discussion with Lane Stoeckle, PCA based in California, on augmentative biocontrol in strawberry production, the use of drones to release predators over large areas, and the challenge of the industry to manage soilborne diseases.
A discussion with Emily Symmes of Suterra on the use of mating disruption and insect traps, and on the future of augmentative biological control in nut cropping systems.
A discussion with Greg Gonzalez of Scheid Vineyards on the importance of the vineyard crew’s role in an IPM program, and on misconceptions about the cost of transitioning to organic.
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