Biological Plans for 2012

Roger McGaughey

This year will be a true test of our biological system and I have every confidence that it will be successful. This spring we will be renting a lot of production space from one of the other greenhouses in town and plan to continue with the systems that have worked so far.

In some ways it will be back to basics with the initial treatment—that is applying RootShield WP by hand to everything that is produced. We won’t have an in-line production RSWP application tunnel so everything will have to be done with a portable Dosatron, like in the early days when I embarked on my “no chemicals” approach to growing. Writing these articles has been rewarding in that I’ve often had feedback with comments or questions: Does it really work? If done properly the answer is an emphatic “Yes!” Coupled with weekly nematode applications, a treatment of RSWP over the top of newly planted material really works to produce “clean” crops.

We’re growing Easter Lilies this year for the first time on our main location. Years ago I was taught to dip the bulbs in chemicals for insect and disease prevention, but this year the bulbs were just dipped in RSWP and nematodes. The planted pots were then drenched with RSWP as our normal procedure and, as can be seen in Figure 1, the root system in the early crop stage is excellent. Things are off to a good start with the crop right on schedule. Nematodes have been applied weekly and so far, my yellow cards are almost completely clean. Nematodes will continue to be applied weekly until the lily crop is harvested.

Last year at this time I was struggling with an aphid supply for my banker plant production. Because our nursery is so clean, a population of Aphidius colemani and ervi still exist and are ready to parasitize our new aphid supply. We are going to have to be very careful with our aphid banker starter plants. I have a larger net this year, which I hope will prove effective. The real bonus of our new location is that since no biological program has been tried there before, there shouldn’t be any initial predator problems. As long as we can secure a good supply of cherry aphid banker plants we hope to bulk up our in-house banker plant stock in February and early March. This will enable us to cover that whole location as we open up the houses for spring production. The banker system works, but in the past we have struggled to keep a continuous supply of new aphids through the spring. We hope that won’t happen this year.

As stated before, weekly nematode applications help keep the thrips population well in check. Orius insidious, another thrips predator I’ve written about before, can’t be incorporated into the program until the temperature warms up in spring. Some good pollen-bearing varieties, .i.e. zinnia, lantana, alyssum, etc., can be used to make planters for outside banker production. Some of our perennial varieties can also be incorporated in these bankers. If our spring aphid supply continues, it will be easier to incorporate A. colemani and ervi into the outdoor banker plants. These predators, in conjunction with the Orius, should help keep the outside growing areas clean. Last year, as seen in Figure 2, I had bankers in our mum fields and we had our “cleanest” mums and perennials to date.

We plan to grow fall mums at our second location as well, so large multi-specimen bankers will be needed there also. New research is being done at some of the universities in an attempt to find not only which plants produce ample pollen, but which species are particularly beneficial to predator reproduction. It’s important to keep in touch with all current publications and our extension service so we can make our programs as successful as possible. Bringing these programs to our customers at their locations, and eventually to the homeowner, can only benefit the industry and the environment as a whole. GT

Roger McGaughey, head grower at Michael’s Greenhouses in Cheshire, Connecticut, was educated in Northern Ireland and England and has 40 years experience as a grower.