Articles
HIGH DENSITY PLANTINGS FOR PROTECTED CULTIVATION OF FRUIT CROPS; NET TO PROTECT AGAINST INSECTS.
This led to a growing interest in pesticide free commodities.
In general, this aim is impossible to achieve under normal growing conditions so that integrated pest management is practiced in order to reduce pesticide use to the minimum.
A different approach to obtain this goal was taken with peaches in the coastal plain of Israel and is described below.
Eight year old Rhodes peach trees on their own roots grown in an intensive meadow orchard system in Israel’s coastal plain were fully covered by a white net.
The small trees (planted at 2.0×0.75 m) were kept at a height of 2.00 m.
The plot was kept clean by manual cultivation followed by covering the soil with brown plastic to prevent weed growth.
Drip irrigation and fertilization through the system were used.
It was found that nets of 16 mesh are dense enough to prevent penetration of flies and moths without changing too drastically the environment to cause negative effects on vegetative or reproductive development.
Light measurements showed the net to reduce light penetration by 15%. A further reduction of 15% of light transmittance in the 400 to 700 nm range was recorded with time, due to dust accumulation.
Maximal temperatures were lower by 1 to 2°C and air humidity was higher as compared to the control.
Vegetative growth was superior in the covered treatment against the control, while flower bud differentiation was reduced but not to a level that caused reduced yield.
The pesticide free fruit obtained was of excellent quality.
Over a duration of 3 years it was shown that spider mites, Tetranychus cinnabarinus and T. urticae were increased to epidemic proportions when shading was increased over the season although the population of the two predators, the phytoseiid mite, Typhlodromus athiasae and the coccinellid beetle, Stethorus gilvifrons increased as well.
A chemical treatment after fruit harvest in mid June was required.
This seems to be controlled by rinsing the net with water and preventing shading buildup.
The population of the olive scale, Parlatoria oleae was increased steadily over the 3 year duration of the trial.
Therefore an oil-DNOC spray in winter time was applied after the third growing season.
No penetration of either the Mediterranean fruit fly, Ceratitis capitata and the cottonseed bug, Oxycarenus hyalinipennis was noted.
Added protection against hail and birds was another benefit of the covered orchard.