In this article we will discuss about some of the strategies to control pests of stone fruits.
Organic pest and disease management in stone fruit orchards is an integrated approach combining cultural, mechanical and biological methods in first place and using botanical and organically acceptable chemicals as last resort.
First and foremost strategy in organic pest management is manipulation of cultural practices to ensure a balance in natural processes, which in turn keep the pests below the economical threshold limit.
Some important strategies are:
A. Giving Crop a Head Start:
1. Grow healthy crop – use of resistant cultivars and disease free planting stock,
2. Maintenance of sterile and hygienic conditions in grafting operations,
3. Proper spacing, mulching and green manuring and adequate use of organic manures and proper irrigation. Close planting including high density planting and meadow orcharding should be avoided.
B. Ecological and Cultural Strategies for Below Ground Pest Management:
1. Frequent growing of legumes on orchard field and its incorporation in soil ensures steady availability of biological nitrogen. Instead of single crop/species, it is always better to have a mixture of 3-5 legumes for green manuring.
2. Keep soil covered with living vegetation and or crop residue.
3. Adequate use of organic manures followed by biomass mulching and drenching of biomass with fermented dung-urine slurry (such as Jivamrit) ensures high activity of beneficial microbes, which act as deterrent to harmful microorganisms and insects.
4. Frequent application of bio-fertilizers especially the mycorrhiza.
5. Frequent drenching of basins of plants (at least once a year) with Trichoderma viride, T. harzianum, and Pseudomonas fluorescens.
C. Ecological and Cultural Strategies for Above Ground Pest Management:
1. Ensure natural habitat and survival conditions for natural pest enemies such as pest predators, parasites and pathogens.
2. Raise the flowering plants/compatible cash crops along the field border by arranging shorter plants towards main crop and taller plants towards the border to attract natural enemies as well as to avoid immigrating pest population.
3. Grow flowering plants on the internal bunds inside the field.
4. Do not uproot weed plants those are growing naturally such as Tridax procumbens, Ageratum sp, Alternanthera sp etc. which act as nectar source for natural enemies.
5. Do not apply strong botanical pesticides, when the P: D ratio is favourable (at 2:1).
6. Reduce tillage intensity so that hibernating natural enemies can be saved.
7. Select and plant appropriate companion plants, which could be trap plants and insect attractant plants. The trap plants and insect attractant plants will also recruit natural enemies as their flowers provide nectar and the plants provide suitable microclimate.
8. Due to enhancement of biodiversity by the flowering plants, numbers of parasitoids and predators (natural enemies) will increase due to availability of nectar, pollen and insects etc. The major predators are a wide variety of spiders, ladybird beetles, long horned grasshoppers, Chrysoperla, earwigs, etc.
9. Collect egg cards of beneficial insects for release such as Trichogramma, Chrysoperla, Telenomus etc. which are available from State Bio-control Labs.
10. Keep monitoring pest: defender ratio – The natural enemies of temperate fruit pests can be divided into 3 categories (a) parasitoids, (b) predators and (c) pathogens. Important natural pest enemies are ladybird beetle, hover fly, green lacewing, spiders, predatory mites, Bracon hebetor and Trichogramma. Keep insectary plants growing around orchards to maintain their population.
11. Install pheromone traps mainly for Apriona, Dorysthenes and Lymantria species. Usually 4-5 traps/ acre are used for surveillance. For effective control 15-20 traps per acre at a height of mid canopy and at a distance of 12-15 feet gives 80-90% control of such insect pests. Keep on watching and clean them. If load is high then use other control measures.
12. Install yellow/blue water pan and sticky traps at a height of mid canopy @ 4-5 traps/acre for observations and 20-25 traps/acre for control. Yellow traps are effective against wide range of aphids and flying insects and blue traps against blossom thrips.
13. Grow flowering plants along the orchard border by arranging small plants towards the crop and taller plants towards border. Flowering plants can also be grown on internal bunds. Important insectary plants that can also planted as intercrops include mustard, sunflower, buckwheat, alfalfa, marigold, carrot, French bean, cowpea, maize, spearmint etc. After flowering these plants can be used as green manure/mulch.
Keep on enumerating pest: defender ratio. If pest defender ratio is 2:1 then no need to worry. If it increases above 2:1 then adopt necessary curative and control protocols.