The weta did not do it

Press, 9 March 1984, Page 14

The weta did not do it

GARDENING

by

M.Lusty

Many of our native plants have enjoyed a very good flowering season. Included in this group is Carpodetus serratus, Marble Leaf, or Putaputaweta. This, the most frequently applied Maori name, which can be rolled around the tongue to make it sound even longer, was apparently bestowed on this tree to indicate the perforations mistakenly attributed to the weta. The alternate leaves of this monotypic genus have a marbled appearance with prominent veination. The flowers, which occur between November and March, have a permeating but pleasant fragrance. Not often seen in gardens, it will grow to about 6m in height. Given good growing conditions, Carpodetus serratus could be left to grow without any need to interfere with its development although it is tolerant of pruning. Gardeners’ queries: I wonder if you could give some advice regarding the growing of butter beans. For years, for the most part, I have had them produce distorted growth — “C” or “J” shaped beans, whether branded seed or self saved. There seems no pattern to it. The only variable I cannot control is the weather. Maybe it’s the variety of seed although there does not seem to be anything else but Golden Wax. W. T. (Chch).

Assessment of the problem is reduced to guess work in the absence of examples. The vegetable bug, a greenish-brown, shield-like insect causes distortion of beans through its sap-sucking feeding habit; it can be controlled by spraying with primiphosmethyl/permethrin or acephate. There is little selection available in the butter bean range of seed but two other cultivars which appear readily obtainable are Choctaw and Brittle Wax.

I have a problem with my polyanthus which noone has been able to advise me about. As you will see the plants are in

very poor condition in spite of having been sprayed with Yates Improved Pest Master. The same problem occurred last year in spite of good soil and feeding. They flowered very well and then the problem occurred. There has been similar trouble with the leaves of my Ranunculus last year. M. D. (Nth Canty). Mites are responsible for the sickly appearance of these polyanthus. These plants are very susceptible to heavy infestations of these pests which can really debilitate them. Dicofol or tetradifon should be used for control; at least two applications should be made, two to three weeks apart. Slugs and snails are also fond of polyanthus so the use of slug bait in the vicinity of the plants is also worth while. The control which you have applied contains dicofol so maybe circumstances reduced the efficacy of the preparation.

Polyanthus respond to good soil and a reasonable amount of moisture at all times; planting should be such that the crown is at ground level not below it. Could you please tell me what is causing the pock

marking of my Bon Chretien pears. It was evident last year, and nearly all the fruit are affected this year. The tree was sprayed with Yates Conqueror all purpose oil in the winter and with carbaryl after petal fall in the spring. Perhaps you could recommend a more effective spray. S. D. (Chch). The black spotting on the pears has been caused by the fungus disease, black spot. This troublesome disease can become very persistent once it becomes established and usually requires careful and repeated efforts to control it, particularly when prevailing conditions favour its development. The disease over-winters on infected, fallen leaves and lesions on the branches, therefore intial control should be to remove such sources of reinjection. Prior to leaf fall, spray with a copper based material and repeat in the winter, at bud movement, and again several times during the spring. Good coverage is essential to achieving adequate control. None of the materials mentioned by you would have any countering effect on black spot. Could you please tell me what is the disease in this Pukekohe onion. The crop has been grown in the same place for nearly 40 years and this has never happened before. Could it be the wet season we have been having. E. S. (Rakaia).

Onion smut has been found on the specimen examined. This fungus can remain in a viable state in the soil for very many

years once it has established itself. Infection can be transmitted by contain-* inated soil adhering to tools, footwear, etc. All diseased onions should be carefully gathered up andburnt. Rotation is very; strongly advised and all’ onion seed should be treated before sowing? Seed treatment found effective consists of mixing' the seed with 50 per cent thiram at half the seed weight to which should be added methyl cellulose (2g in 45 cc lukewarm water with 200 g seed). Alternatively, apply diluted formalin (10ml to 695 ml water per 7m of row) to the drill at planting time. The wet weather may have contributed to the development of the disease in your garden. Could you please tell me what disease or pest my celery is suffering from, and suggest remedies. The leaves are spotted and discoloured as though they are dying and some have brown grooves eaten into the stem. In spite of this the plants continue to grow new stalks. I enclose samples. E. R. (Chch). You have provided a very good description of _ the advanced stages of-' celery leaf spot, apart" from including samples of the infected plants. Again, we are dealing with a' very persistent and pre valient disease. Periodic . spraying right from the • time of planting out isr' advisable to maintain a disease-free crop; apply a * copper-based spray, of zineb. Remove all badly diseased vegetation and burn it. New growth will become infected unless ‘ control is applied.