Whitefly was starting to become a serious threat to Colonial Florists’ poinsettia crop. The problem was brought under control with a combination of parasitic wasps. Biological crop protection is becoming more and more important for this Canadian company.
Colonial Florists is based in St. Catharines, Ontario, not far from Niagara Falls. The company’s premises are spread over four hectares. Depending on the season, Colonial Florists employs between 30 and 60 people. The company propagates young plants for pot plant growers in central and eastern Canada and the United States. It also supplies retailers in the Toronto area and the north-east coast of the USA with adult pot plants and hanging plants. With more than one and a half hectares of cultivation area, poinsettia is one of their main crops. Their other crops include cyclamen, geranium, impatiens, and calibrachoa. Altogether, they have more than 500 varieties. In order to continue to satisfy the growing demand, Colonial Florists also rents additional cultivation space in the spring.
The most important form of defence
Within the company of the Van der Zalm family, who moved to Canada from the Netherlands many years ago, biological crop protection has been the most important defence against insects since 2007. Whitefly (Q biotype) started to form a particular threat in poinsettia cultivation. The Lewis mite also caused problems recently. Rob van der Zalm from Colonial Florists explains: ‘The traditional chemical agents used to combat whitefly were no longer effective. Due to excessive use within companies outside Canada and the United States, the Q biotype had become more or less resistant.’
A great improvement
Combating whitefly using natural enemies initially brought variable success. During these few years, the company worked closely with the local Vineland Research and Innovation Centre, which compared the whitefly control methods at a number of different companies - purely chemical methods, purely biological methods, and combined methods - and shared the findings. Four years ago, Colonial Florists made contact with David Neil at Koppert Canada. ‘He suggested using Enermix, a combination of the parasitic wasps Encarsia formosa and Eretmocerus eremicus,’ says Rob van der Zalm. ‘We decided to make the switch. The success rate was not 100%, but the Enermix approach did result in a great improvement straight away.’
Improved plant health
Thanks to biological crop protection, the all-round health of the plants improved, and damage caused by chemical spray applications (such as stagnated growth and leaf damage) has been greatly reduced. ‘In the first few years, the expense of natural enemies was a great concern, particularly in situations in which we had to temporarily abandon the biological approach and chemical-based measures had to be taken. However, the last few years have been very successful. We are now further refining the strategy every year. We hope to be able to boost our success even further in this way.’
Reduced use of chemicals
‘A family business - rooted in quality’: that is the slogan of Colonial Florists. The drive to continually improve quality partly explains the decision to use biological crop protection. The market also plays a role, as the biological approach is becoming more and more important every year in terms of sales. Rob van der Zalm continues: ‘Today’s end consumers consider the environment in their purchasing decisions. This is also an issue for the colleagues to whom we supply young plants. They can base their biological crop protection on ours, and if they decide not to, then we have still helped them up to that point. After all, as we use so much less in the way of chemicals, the risk of pests developing resistance to them has declined. All markets are moving towards reducing the amount of chemicals used.’
Wanted: a strategy to combat aphids
Colonial Florists is well advanced in the biological control of whitefly and thrips. Challenges do still remain, such as the Lewis mite and aphids. ‘There are natural enemies available to combat aphids, and we were able to control this pest in the past but only after the damage had occured. However, we would like to further our preventative strategy in combating this pest so that we stay clean throughout the entire production process and also for the end consumer. After all, aphids cause visible, cosmetic damage to the crop, and that damage cannot be simply polished away. The strategy that we are seeking in collaboration with Koppert is preferably a biological solution. After all, the use of neonicotinoids is coming under pressure due to their effects on bee populations.’ The contact and the communication with Koppert (previously David Neil, now Adam Hendriksen) are important for Colonial Florists. ‘The success that we are enjoying with natural enemies is directly linked with good consultation with Koppert.’
For more information
Koppert Biological Systems