Sender: pbs-admin@lists.ibiblio.org Errors-To: pbs-admin@lists.ibiblio.org X-BeenThere: pbs@lists.ibiblio.org X-Mailman-Version: 2.0.13 Precedence: bulk Reply-To: pbs@lists.ibiblio.org List-Help: <mailto:pbs-request@lists.ibiblio.org?subject=help> List-Post: <mailto:pbs@lists.ibiblio.org> List-Subscribe: <http://www.pacificbulbsociety.org/list.php>, <mailto:pbs-request@lists.ibiblio.org?subject=subscribe> List-Id: Pacific Bulb Society <pbs.lists.ibiblio.org> List-Unsubscribe: <http://www.pacificbulbsociety.org/list.php>, <mailto:pbs-request@lists.ibiblio.org?subject=unsubscribe> List-Archive: <http://www.pacificbulbsociety.org/pbslist/old.php> <<> Can you elaborate about your homemade bulb cooker that you use to control the Narcissus fly and what exactly you do? It sounds like Narcissus may not always be a bulb you can safely plant in the ground in the Pacific Northwest and leave. <<> As with so many parasites, the Narcissus fly seems to leave completely alone things of little value. Of course, as Murphy would have it, the most valuable things seem to fall victim to it. I have driven around the Willamette Valley extensively in the Spring and have often been amazed the quantity of feral daffodils one will find. Apparently, at one time many years ago, the ubiquitous yellow trumpet one sees growing everywhere in Spring was planted in bulb growing fields for cut flowers and dry bulb sales. Those fields are now often pastures. The bulbs that were missed when the fields were dug have since multiplied into great swaths of yellow flowers visible from some distance. And, as I previously mentioned, fence rows and gardens everywhere each Spring sport enormous quantities of daffodils. So, despite the Narcissus Fly, daffodils survive and bloom each Spring and, for most people I suppose, it's of little concern. While it may not concern them, these plantings are reservoirs for the insect. When the flies emerge in Spring, they mate and the females start looking for $50 daffodil leaves -- yours -- on which to lay their eggs! The egg is laid at the base of the leaves where it hatches a few days later. The larva crawls down the leaf to the bulb where it enters at the base (usually) to begin feeding. It remains in the bulb until early Spring when it exits the bulb to pupate in the warming soil. The adult fly emerges a short time later to begin the next cycle. While the life cycle of this insect indicates parasitism of tunicate bulbs, the bulb is usually not entirely destroyed (if it's large enough). Rather, with elimination of the apical meristem, the secondary meristem sprouts and, while the main growing point is destroyed, it is replaced with a number of smaller bulbs that take a couple of years to reach blooming size and, once again, become food for the next generation. Daffodils are prone to several parasites. The best defense, in this case, is a good offense: very carefully examine any tunicate bulb you intend planting on your property to make absolutely certain that it is free of disease and parasites. I can guarantee you the cure will always involve more effort than prevention! Of course, ordering from reputable firms is the first step. Hot water held at a certain temperature for a specified length of time was developed by an English researcher named Ramsbottom to combat the bulb and stem nematode then decimating English bulb stocks in the 1920s. 114 deg. F for three hours is said to rid the bulb of this parasite. One has to be extremely careful with this process, however, as this temperature is borderline between curing or killing. Slightly lower temperatures and shorter immersion time, i.e., 112 deg F for 1.5-2.0 hours in early-mid August will kill the fly larvae burrowing in the bulb. The bulbs have to have been dug and kept warm and dry for several weeks after being dug before this treatment is attempted as it can damage the newly formed bud that will only form after the bulb has been held at 70-75 deg F. for six weeks. Certain chemicals are often added to the water, in particular to deal with nematode infestations and Fusarium. A common one is formaldehyde, now banned in many places. The replacement would seem to be peroxyacetic acid. To aid in heat penetration, surfactants are also added and to control foaming that occurs when the solution is agitated, antifoaming agents are also added. "Bulb cookers" range from professional units that are used to sterilize bottled products to large watering troughs, down to something that has been called the "garbage can bulb cooker." This was developed by Marie Bozievich (a noted daffodil grower) and seems to work fairly well. One starts with a large garbage can (often plastic, but galvanized will provide greater rigidity). One needs to figure out how to insulate it to aid in maintaining a uniform temperature throughout the bath. A thick layer of very firm Styrofoam larger than the base will work to prevent heat loss from the bottom. The can itself can be wrapped with several layers of Fiberglas house insulation (wear gloves, eye protection and long sleeved clothing as broken pieces of the insulation fibers can be very irritating). It's wise to have a valve mounted near the bottom of the can and enclose the whole thing in a wooden frame that can be permanently insulated and covered over. With the valve in place, water can easily be drained from the container without soaking the insulation. One needs a heater, usually a hot water tank heater of some sort will work. The can has to be fairly tightly lidded to maintain an even temperature. A circular piece of thick marine plywood is best and three holes are made in it. The lid is then varnished (with marine varnish) on both sides. The central hole requires a cylinder of heavy hardware cloth be formed (and that allows at least one inch between its wall and the propeller) and fastened to the underside. This will contain a "drill bit" that has been formed from a rod on which a small propeller has been welded. This fits into a device to turn the rod (a variable speed electric drill mounted on the topside of the lid and whose speeds can be set and left) at a desired speed. This circulates the water in the can. Another cylinder will contain a thermometer and the third will contain a thermostat. The heater is set into the can, also protected from the bags of bulbs; it's best if it is set near the bottom of the hot water bath. The thermostat can be set into the lid or run down the inside of can and protected from the bags of bulbs it will eventually contain. Do not scrimp on the instruments, as they must be of high quality and accurate. Temperatures outside of the treatment range will kill the bulbs, often a greater loss than the cost of the instruments. As with many things, there is the best way and then various modifications that compromise the process but are cheaper. Caveat do-er!! I've seen this process used with chest type deep freezers modified with the necessary equipment down to large Styrofoam picnic containers heated with aquarium heaters, a thermostat and an aquarium air pump to circulate the water and maintain a uniform water temperature. Irrespective of what is being used, the important thing to remember is this: the water must be maintained at a uniform temperature throughout the container for the specified time, or there will be problems. An accurate thermometer is essential. Circulation of the water tends to be the biggest problem with the can cookers. One hard and fast rule is don't overload the unit! I used several bricks on the bottom of the can to keep the bulbs off the bottom and aid in circulation. Ultimately, I made a cylinder that reached to and sat on the bottom for ease of use and stability. The rod also contained more than one propeller welded on. This created considerable centrifugal force keeping the water at the required temperature without creating pockets of overheated or underheated water. This cylinder was set into the can, the bags of bulbs loaded into the preheated water (a quick way is fill the container directly from a hot water heater), the lid set into place, the agitator rod inserted into the drill and the drill mounted into place on the lid. The last steps were to connect the thermostat and heater and to insert the thermometer into its protected cage. Loading of the unit will substantially lower the temperature. Timing cannot start until the temperature stabilizes at the desired treatment temperature. One way to shorten the interval is to soak the bags of bulbs for a couple of hours in water kept warm and to which a surfactant has been added. When the cooker is ready, load the bags of warm bulbs directly from the bath into the cooker. Once they've been treated, the bags of bulbs are removed, drained and immediately hung in a shaded airy place to cool and dry; fans help. Planting should be done within a few weeks after treatment for best results. In many areas, daffodils will root at the merest hint of moisture. I have dug daffodils in the heat of August (especially poeticus and Division 9 hybrids) only to find they had thrown the new set of roots. This is one of the reasons I am death on weeds because I have found the leafy biennial types, in particular, to concentrate moisture in the soil, whether by condensing the dew or from transpiration I don't know, but under the right conditions, it can be a problem. Plus, weeds need to be controlled for all of the other reasons one does so! While absence of weeds makes spraying more effective, it also makes it easier for the female fly to find a set of daffodil leaves particularly to her liking. Hot water treatment is an effective method for controlling bulb fly. While the process may appear complex, like any process, with organization and practice, it becomes routine. However, its effect will last only one season, as treatment does not preclude re-infestation from outside of your growing area. It is actually easier to spray (with a contact insecticide, e.g., Dylox or Dursban) several times during fly season or to make beds that can be sealed off with fabric from the late bloom period to senescence of the leaves. Some apocryphal evidence seems to indicate that systemic insecticides are effective. For these things to be effective, the chemical would have to be resident in the bulb tissue (as the newly hatched larva does not begin eating until it reaches the bulb itself) and that would mean, I would think, that treatment would have to be frequent during the growing season and at least one year prior to the anticipated damage. I've never encountered the bulb and stem nematode (extremely difficult to eliminate; actually, the best cure is to abandon everything, sell the property and move!!) but have used this method to eliminate bulb mites from stocks. I now use sprays almost exclusively for control of bulb fly, primarily for its ease of use and effectiveness and due to the size of the operation. Dave Karnstedt Cascade Daffodils Silverton, Oregon Maritime Mediterranean climate email: davekarn@AOL.com