Tag Archives: New Zealand

No Kiwifruit Exports from New Zealand Without Insecticide Sprays

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Leafroller Damage to Kiwifruit

Leafroller Damage to Kiwifruit

New Zealand accounts for 33% of the world’s trade in kiwifruit, exporting about US$450 million annually. Kiwifruit production in New Zealand is entirely oriented toward the export market. The domestic market is small and is flooded with fruit that do not meet export standards. In the early days when it was only a minor crop , no sprays were applied. Today, presence of insects, scales, or insect damage can cause rejection of an orchard’s entire crop.

“In the early days of growing kiwifruit in New Zealand it was considered a crop that didn’t need spraying. The very small amount of fruit produced was sold on the New Zealand market without any major problems due to pests or diseases. Predictably as the area planted increased, and more fruit was submitted to the scrutiny of export inspection, more pest and disease problems were encountered and more sophisticated methods of control were required… Kiwifruit are readily attacked by leaf roller caterpillars, and as plantings developed it became apparent control measures were necessary, especially for export fruit.

There are still a few small growers who never spray at all, but their fruit is seriously damaged by leaf roller caterpillars, and there is no chance of such growers being able to export kiwifruit as fresh fruit.

As exports developed in the late 1960s greedy scale was noticed in significant numbers on the fruit and became a problem in meeting international quarantine standards. Greedy scale was not a debilitating pest to the crop, nor was it a problem to local market fruit, but for export fruit it had to be controlled along with the ever present leaf roller.”

 

Author: Sale, P.R.
Affiliation: Ministry of Agriculture and Fisheries, Tauranga.
Title: The history of pest and disease control in kiwifruit.
Source: Proc. 33rd N.Z. Weed and Pest Control Conf. 1980. Pgs. 110-113.

Insecticides Required to Meet Consumer Demands for Blemish-Free Carrots in the EU

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nasty carrots

Carrot Fly Damage

Carrot is one of the most important vegetable crops in the EU with 6 billion pounds of annual production. The carrot fly is the major insect pest of the carrot crop in Europe. Before the introduction of insecticides in the 1950s, the carrot fly typically damaged 20-50% of the carrots grown in Europe. In some parts of Europe, the damage from the carrot fly was so severe that it was not profitable to grow carrots. Today, European carrot growers spray insecticides to prevent damage from the carrot fly.

“Carrot fly, is the most widespread and serious pest of carrot, parsnip, parsley and certain other umbelliferous herbs in temperate regions of the world. … The insect has two and, in some parts of Britain, Europe and New Zealand, three generations each year. Adult insects feed on the nectar and pollen provided by flowers and spend most of their life in the hedgerows, ditches or amongst herbaceous plants in gardens. Females search out carrot plants to lay their eggs which are inserted in crevices around the crown of the host plant. The larvae, which emerge from the eggs, migrate downwards to feed on plant roots.

Carrots grown commercially can be rendered unmarketable by even slight carrot fly damage.

To meet the stringent levels of blemish-free produce demanded by the supermarkets in the UK and Europe, commercial carrot production depends precariously on a few insecticides to control this pest.”

Author: Ellis, P. R.
Affiliation: Horticulture Research International, UK.
Title: The identification and exploitation of resistance in carrots and wild Umbelliferae to the carrot fly, Psila rosae (F.)
Source: Integrated Pest Management Reviews. 1999. 4:259-268.

Herbicides Prevent Blindness in Sheep

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Sheep - NZ Pasture

Sheep – New Zealand Pasture

Eye Damage From Barley Grass

Eye Damage From Barley Grass

New Zealand is well-known for its lamb. Sheep and lambs feed in pastures. Barley grass is a common problematic weed in New Zealand pastures. The barbed spikes on barley grass seed can penetrate the eyes of sheep and can cause painful lesions, infections and blindness. Weight loss in lambs is attributed to their reluctance to feed in pastures infected with barley grass. Herbicides are used to remove the barley grass and early research in New Zealand demonstrated the benefits.

“An area of uniform barley grass (Hordeum murinum) infestation, in Waikato, was divided into twenty-four 0.2ha paddocks. Three chemicals… were used to control barley grass and the paddocks were grazed by lambs throughout the summer at two stocking rates.

All the chemicals reduced the barley grass content of the sward by over 96%, with pronamide giving 99% reduction, and significantly reduced Poa spp.

During the first month of the grazing period, the lambs on all chemical treatments at both stocking rates gained weight at approximately twice the rate of those on the untreated paddocks. …The control lambs (untreated paddocks) stopped gaining weight in mid-January and started to lose weight at the higher stocking rate.

The sudden growth check among the control lambs in mid-January coincided with maximum seed shed of the barley grass and is almost certainly attributable to the physical damage caused by the barley grass seed, especially to the eyes.

Initially the eye damage recorded was barley grass seed in the eyes but, at later stages, conjunctivitis and keratitis resulting from seed puncture and abrasion of the cornea.

During late January and throughout February, many of the control lambs were completely blind and were a pitiful sight. …this paper gives a clear indication of the benefits to stock and pasture that can arise from herbicide treatment.”

Authors: Hartley, M. J., and G. C. Atkinson.
Affiliation: Ruakura Agricultural Research Centre, Hamilton.
Title: Effect of chemical removal of barley grass on lamb growth rates.
Source: Proceedings of the New Zealand Plant Protection Society. 1972.

Apples Can be grown in New Zealand Thanks to Fungicide Sprays

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Apple Scab

Apple Scab

Apple scab is the most economically important disease of apples in the world. Fungal scab infections cause cracks in apples. Infected leaves fall off the tree which can result in reduced tree growth for one to three years. Apple growers worldwide have been spraying fungicides for over 100 years to control scab. And in New Zealand…..

“New Zealand apple industry spray programmes for control of black spot (scab), caused by Venturia inaequalis, typically use 16-20 fungicide applications each season, including dodine and fungicides in the demethylation inhibitor (DMI) group. These fungicides are particularly important to orchardists because their systemic activity prevents black spot development when they are applied after infection has occurred.”

Authors: R.M. Beresford1, P.J. Wright2, P.N. Wood3 and N.M. Park3
Affiliation: 1The New Zealand Institute for Plant & Food Research, Auckland, New Zealand; 2The New Zealand Institute for Plant & Food Research, Pukekohe, New Zealand; 3The New Zealand Institute for Plant & Food Research, Hawke’s Bay Centre, Hastings, New Zealand.
Title: Sensitivity of Venturia inaequalis to myclobutanil, penconazole and dodine in relation to fungicide use in Hawke’s Bay apple orchard.
Publication: New Zealand Plant Protection. 2012. 65:106-113.