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Read about experiments conducted at the Pukekohe Research Centre in 2006 on a Patumahoe Mottled Clay loam (ph6.5).

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The following research information has been provided to us by Alzchem Germany, the manufacturers and marketers of PERLKA.

Pink Root (Pyrenochaeta terrestris) affects onions, garlic, leeks and shallots. The disease is active to a depth of up to 45 cm in the soil. When air temperatures reach 24- 28 degrees Pink Root disease activity accelerates and is often seen on onion roots. Fusarium regularly works in conjunction with the Pink Root infestation.

Perlka gave good control of Pink Root in a hybrid onion crop when applied 14 days before sowing, reducing the instance of root and plant infestation by almost 60% compared to the control. The standard control application was Ammonium Nitrate. The soil type was a medium loam with pH of 7.3. Perlka is 19.8% Nitrogen and 50% Calcium Oxide.

Perlka distributor in the United Kingdom, Paul Corfield has extensive experience with Perlka use on onions. This includes using rates of Perlka at 400 kilo /hectare on onions. The grower considered the results to be a success with improved strength of the foliage resulting in a high quality skin finish and firmer, more dense bulbs. At these same rates, there also appeared to be good control of Fusarium.

The non-leaching benefits of Perlka resulted in the grower requiring less nitrogen. This benefit, coupled with the crop having more available Calcium makes Perlka an ideal fertiliser for onions.

What is Perlka

Perlka is manufactured from natural raw materials, coal, limestone and atmospheric nitrogen. When combined with electricity they form a well proven nitrogen fertiliser.

Perlka is composed of

• 19.8% Nitrogen : less unwanted nitrates without a drop off quality.

Perlka is a long term nitrogen source that has to go through several transformation processes in the soil to become fully available to the plants. The nitrogen supply corresponds to the natural growth demands of young plants. Ammonium nitrogen remains in the soil for a long time. Loss of nitrogen through leaching is minimal making Perlka the ideal fertiliser for irrigated crops as well as crops grown in areas of high rainfall. Throughout onion production areas of New Zealand this is often the case, especially in the 4 month period after sowing.

• 50% Calicum oxide: This is readily available to the plant via soil moisture.

Perlka has a lime content of 50% (CaO). This is highly reactive and long term use of the product has shown that the pH of the soil will remain constant without further additions of lime.

Worldwide scientific reportage has identified that physiological disorders in vegetables are on the increase. These include tip burn in lettuce, black heart in celery and blossom end rot in tomatoes. Regular applications of Perlka can help to reduce these problems.

Over 50 years of Perlka use studies filed in Europe have shown very positive soil fertility effects from periodic applications of Perlka. These have been due to major increases in soil microbial enzymes, which are well regarded scientifically to be an indicator of soil fertility.

What is the effect on the plant?
Also commonly known as Lettuce Drop it causes the lettuce to eventually totally collapse. Over time there will be almost nothing left to see, but a space in your row. It first appears as small angular pale brown to grey-brown lesions. This then leads to severe degradation of tissue and resulting mushy rot. Ideal conditions for both species of Sclerotinia are wet – damp conditions. However S. sclerotiorum does require more humid conditions to develop and produce the sclerotia or fruiting bodies which produce the aerial spores.

How long can Sclerotinia survive?
Both species produce sclerotia which act like seeds. These sclerotia can survive in dry soil for up to 10 years. In wetter conditions it can be less at around 3-4 years in the absence of a host. The mycelium on the other hand survives on plant debris. The seeds or sclerotia of S.sclerotiorum are smaller, more angular and more numerous.

How to control Sclerotinia.
Control is a blend of chemical and cultural practices. This includes the use of fungicides, bio-control agents, crop rotation and soil amendments.

Crop rotation with any other crop will reduce the incidence of S. minor as this is lettuce specific, but is not so effective on S. sclerotiorum due to its wide range of host plants. A fallow period is not as effective at reducing the sclerotia as the effect of regulated wetting and drying of soil during a crop. Ideal crop rotation is 3-4 years and the use of Sclerotinia non host plants. This is not always that practical.

Fungicide efficacy is affected by disease pressure, weather conditions, method of application, overuse and crop canopy. Fungicides must be directed at the base of young plants to have any chance of being effective.

Biofumigants use the properties of some plants for disinfecting the soil. This includes some types of specialist mustards. Some soil amendments with high content of nitrogen have shown the ability to reduce sclerotia carry over. An example of such a product is Perlka.

Often it is a combination of several or all of these practices which is most effective in controlling Sclerotinia.

ADDER maturity is 8-10 days later than our summer variety VIPER. ADDER has good heat tolerance producing heavy heads, which hold density up to 120mm head diameter. ADDER has a medium to large stem and requires minimal trimming.

ADDER – has medium size beads with a medium high domed head and is medium to dark green in colour. It has shown good disease tolerance. Our best results have been seen under warm climate conditions for the harvest period early summer through to autumn. In the upper north we have had promising results in early winter.

Maturity (depends on planting region)

Summer maturity: 65 – 75 days
Autumn maturity: 75 – 80 days
Early Winter maturity: 85-95 days

Processing Supersweet Yellows: A pleasant surprise was the performance of HY 1656. A high coloured yellow which has performed well in Gisborne, Hawkes Bay and Blenheim. Good yield, recovery and a strong plant. Galaxy remains a quality performer for use as IQF kernel with great factory recovery. We were able to see again the exciting varieties from last year: HY 2282, 2283, 2795 and 2786. All with great colour.

In addition to these there were two new numbers 4739 and 2354. Great colour and slightly earlier to mature, more along the lines of a Krispy King type. The plant styles, rowing, kernel depth and husk cover make these must trial varieties. Growers and processors will follow them with interest.

Freshmarket Sweetcorn: Do not forget our market leading early bi-colour, Entree for a proven, reliable start to the season. For yellows HY 1027 is an excellent early and approximately the same maturity as Entree. HY 1027 has great colour, rowing, flavour and a nice deep kernel. Worth a look early! For a main season yellow you can not go past Galaxy. Galaxy has a strong plant, rust resistance and great tasting corn.

Tudor Prince has shown to be a superior pumpkin. Tudor Prince is a medium dark battle ship grey with vibrant orange coloured flesh. Tudor Prince is showing great potential to be a market leader. Tudor Prince has been commercial for 2 years now and many growers are impressed with the consistent above average yields and excellent storage potential of the variety.

Brendon O’Connor of Opiki had this to say: “I have been growing Tudor Prince for a couple of years now and have been impressed with the inside and outside colour of the fruit. The other key attributes of Tudor Prince would be the high yields and keeping qualities of this pumpkin.” Tudor Prince is a main season variety and is almost always up to 7 days longer than its early maturing cousin Pacific King.

Pacific King is one of the first pumpkins to hit the market in early December proving its ability as an early maturating pumpkin. Pacific King continues to offer consistency and uniformity in all major growing areas of New Zealand.

The new commercial pumpkin variety from our breeders is called Windsor. Windsor is a variety producing large fruit from 3.5-7kg. Windsor has been trialed over the last two seasons and has shown promising results for the cutting market. Brendon remarks “I also grew a trial block of Windsor (HSC 149) pumpkin this past season, which I think has potential in the cut pumpkin market. A very large ribbed pumpkin with deep flesh on the shoulder and good internal colour.” Windsor has a small seed cavity and high a shoulder which results in great flesh recovery. Windsor has a distinctive deep rib and scallop shape with excellent internal colour. Commercial seed is available for the 2011/12 season.

Carbide continues to produce good skin numbers, quality and stores well. Results were good from Pukekohe to Canterbury. Maturity is RLK or a little earlier depending on conditions and growing location. The selection has taken time and bulb focus to get to this point. Seed bulbs in 2011 have been stringently selected to give us better quality and purity for 201.

For the 2011 sowing season we have sold a good amount of seed, which means many of you will get a very good look at Carbides performance, come harvest 2012. We have stored bulbs from February 2010 harvest seen here in the photo.

Our new introduction is Royal Jewel. A Royal Armada type, but different. Fruit size is smaller and much more in line with the size required by the NZ market. The rind is slightly darker, the flesh a deeper red and denser. Everyone has a different opinion of flavour, but in our opinion all the varieties we sell pass the test more than adequately. One of the overriding problems has been the occurrence of hollow heart in seedless watermelon. We have selected vigorously for varieties tolerant to this growth issue. We feel that genetics do play an important role alongside the use of nitrogen and environmental conditions.

We have a range of seedless watermelons available, some of which are marketed exclusively by certain companies. Contact us a to discuss your options.

Many use it as a bulb beet for fresh market. Harrier has good vigour, strong tops that stand up well under stress with a medium sized attachment. The leaves in contrast to the bulb present well as a freshmarket beetroot for bunching. Success also includes babybeet, again with nice presentation, uniform bulb shape and size. This consistent uniformity also carries over for potential use in processing as a slicing beetroot.

Harrier has great colour, no zoning and yields well. It is a must try for any beetroot grower.