Crop Update

This is the first ginseng crop update for the 2009 growing season. We have been experiencing cooler temperatures this April than the same period last year. This is likely to slow down ginseng emergence compared to last year. Emergence may be variable this year due to the lack of snow cover over the past 2 months and the fluctuating temperatures over that period. It is possible that gardens with a southern exposure and the south side of beds may emerge faster under these sunny but cool conditions. Ginseng in older gardens is beginning to emerge in some areas. Monitor gardens closely and ensure that glyphosate products are not applied once any plants have begun to emerge through the soil. If Quadris has not been applied to seedling gardens for Rhizoctonia control, it should be put on as soon as possible and before the seedlings emerge. Quadris can be extremely toxic to some varieties of apple and crabapple. Do not apply where there is the possibility of drift onto apple trees. Application before a rainfall will improve penetration of the product to the root zone. 

There may be continued issues with Phytophthora root rot after the heavy rains in 2008. The first application of Ridomil Gold should also have been applied to older gardens. Once plants have 20% emerged, the first application of Bravo is recommended for protection from Alternaria and Botrytis. Consult all of the product labels and product rates and application directions.

Cylindrocarpon – What to Look for Following Last Year’s Rains

Cylindrocarpon can remain active at very low soil temperatures. With the heavy rains experienced in 2008, damage due to Cylindrocarpon was observed on older gardens. In addition, Cylindrocarpon was suspected of causing or contributing to a scattered wilt in 2-year gardens. It is possible that Cylindrocarpon continued to spread over the fall and spring months when soil temperatures were near freezing. Not all strains of Cylindrocarpon rapidly spread through the soil. It is important for ginseng growers to check spots where Cylindrocarpon was suspected in 2008 for continued spread. Periodically digging up roots in these areas is the only way to know how rapidly the disease is spreading. This will provide a good idea of the potential risk and extent of Cylindrocarpon damage by harvest. 

Figure 1. Cylindrocarpon damage on a ginseng root.

Ginseng Garden Walker Workshop

This workshop will discuss what we are finding this spring in ginseng gardens and how to deal with pest pressures this season

SIMCOE RESEARCH STATION AUDITORIUM
Tuesday, May 26th
7:00 – 9:00 p.m.

NO CHARGE!
Bring samples with you for diagnosis and discussion.
Bring a copy of publication 610 if possible.

The Hidden Cost of Damaged Nozzles
Dr. Jason S.T. Deveau, Application Technology Specialist

Many factors contribute to a successful spray application: sprayer mechanics, application method, weather conditions, nature of the target, product applied and the aptitude of the operator. All of these factors converge when the spray leaves the nozzle. It is therefore surprising that the most critical part of the sprayer, the nozzles, are so often neglected. Monitoring nozzle performance pays financial dividends because tip damage has a direct impact on product effectiveness and cost (see Table 1). If the application is seriously compromised, the operator might have to re-spray, which incurs additional labour, time, fuel, and wear-and-tear on equipment.

Table 1. The Potential Impact of Damaged Nozzles.

The solution lies in proper maintenance and early detection. Tip orifices have delicate edges, so clean them with a soft-bristled brush or using a can of compressed air. Even a wooden toothpick can distort some plastics, so imagine what a wire does. Better still, carry spares for quick field replacements and clean them later in the workshop where they won’t get lost. Be sure to clean nozzle screens with a brush as well because flushing does not dislodge build-up. Nozzle performance should be tested during each calibration (before and mid-way through the season at minimum) or whenever damage is suspected. Testing is simple, quick and inexpensive:

1. Temporarily install a pressure gauge on the boom behind the nozzle (commercial or home-made);       
2. Adjust the regulator to compensate for the pressure change between the pump and nozzle to accurately set nozzle pressure;           
3. Use a graduated container or commercial tip-tester to measure the discharge of clean water over a one minute interval;           
4. Compare the rate to the manufacturer’s rate or compare the flow rate from the used tip to the flow rate of a new tip of the same size and shape.

If the flow rate is 10% (or even 5%) more than the ideal rate, replace ALL nozzles, not just the ones that appear damaged. Replace them once a year or at the first signs of deterioration, whichever is first. The cost of renewing an entire set of nozzles is a fraction of the potential cost of wastage and potential crop damage:

Example: 
A boom sprayer with 10 nozzles sprays a product that costs $40/hectare (~$16/acre). Nozzle tips are worn by an average 10%, which sprays an additional $4/hectare ($1.60/acre).
10 new ceramic hollow cone tips and gaskets cost $50 at $5 each.
The nozzles pay for themselves in 12.5 hectares (31.25 acres).

The rate of tip wear depends on spray pressure, product sprayed, and the material of which the nozzle is made. Upgrading to a harder, more durable tip can reduce maintenance costs. Never mix nozzle materials on a boom; from softest to hardest: 

Brass > Stainless Steel > Plastics > Hardened Stainless Steel > Ceramic. 

Inevitably, all nozzles wear out so be sure to include regular nozzle maintenance and replacement in every spray program.

Questions about ginseng can be directed to Sean Westerveld, OMAFRA’s Ginseng and Medicinal Herbs Specialist at 519-426-4323; E-mail: sean.westerveld@ontario.ca.