Walnut Stage wise IPM

Pre planting

Common cultural practices:

• Destroy the alternate host plants
• Sow the ecological engineering plants
• Sow sorghum/maize/ pearl millet in 4 rows all around the main crop as guard/barrier crop
• Plough the field before planting to destroy existing weeds in the field.
• Apply manures and fertilizers as per soil test recommendations.
• Grow the attractant, repellent, and trap crops around the field bunds.
• Proper selection of cultivars having commercial value and suitable for effective cross pollination
• Before planting of walnut trees, the proper soil selection be made, and the most suitable soil is loam with abundant organic matter.
• Irrigate the plants I - 2 fortnights before expected harvesting.
• To avoid wilting due to long dry spell of summer irrigate the plants.
• Orchard management practices be followed strictly like clean cultivation.
• Arrangement of efficient pruning tools be made before undertaking pruning job.
• If the plants / trees exhibit the deficiency of micronutrients, especially of boron go for the application of the same on the basis of soil and leaf analysis.
• 2 or 3 varieties of walnut are required to be planted for adequate pollination.
• Apply balanced dose of chemical fertilizers and FYM to up keep the vigour of the plant and to reduce the attack of shot hole, back beetles and other pest.
• Growing of flowering plants, especially Marigold and Maize on peripheries and legumes as inter cropping help in conservation of both predators and parasitoids and helps in nematode management.

Nutrients

• Nutrient should be applied on the basis of soil test report and recommendation for the particular agro-climatic zone.
• Prepare land by ploughing and harrowing.
• The pits are dug in summer about a fortnight before planting and left undisturbed.
• Pits of about 1m x 1m x 1m size are dug at a distance of 10 meter in square system of planting.

Water management

• Proper drainage as crop is water sensitive

Weeds

• Plough the field before planting to destroy existing weeds in the field.

Planting

Common cultural practices:

• Collect and destroy plant parts infested with insect pest and diseases
• Use weed free, healthy suckers for planting.
• Remove and destroy crop residues.
• Avoid planting during wet weather condition
• Take up planting in shade free area
• Avoid planting of pest infested saplings.

Common mechanical practices:

• Prune and destroy the scale, borer and canker infested twigs / branches.
• Clip of diseased/ mildewed shoots.
• Remove and destroy dead and drying trees from the orchards
• Collection and destruction of egg masses of hairy caterpillar.
• Collect and destroy the fallen walnut weevil infested fruits.
• Whenever infestation of mealy bug is noticed, slippery bands of alkathane sheets above the ground be applied during April.
• Collection and destruction of fallen foliage in autumn.
• Burlap skirts around the tree trunks infested with hairy caterpillar for collection and destruction of larvae I pupae of the pest from May to end of June.
• Cover the exposed part of the stem to sun with dry grass or gunny bugs soaked with methyl parathion (0.1%) once a month from March to October for
• Controlling borer infestation.
• Complete collection, destruction of foliage and pruned wood in the orchards after leaf fall.
• Fallen fruits be collected and destroyed at every 10 days interval on the community basis

Nutrients

• Planting is done in pits already filled with top soil and farm yard manure in 2:1 ratio.
• Add mycorrhiza culture @ 50 g/pit or a basket of soil taken from old walnut orchard to ensure mycorrhiza association with walnut roots.

Weeds

• Use weed free seedlings for planting.
• Remove weeds from the pits before planting.
• Grow the recommended cover crops between the rows of walnut trees with recommended agronomic practices.

Pests, soil borne pathogens and other diseases

Cultural control:

• Care should be taken that water should not stagnate near the root zone

Powdery mildew

Cultural control:

• Use healthy infestation-free plants.
• Aphids usually spread through infested stocks, avoid planting infested stocks

Aphids

Cultural control

• Use resistant root-stocks belonging to Malling Merton series.
• Ecological engineering with buckwheat attracts parasitoid, Aphelinus mali

Vegetative stage:

Common cultural practices:

• Collect and destroy crop debris
• Collect and destroy disease infected and insect damaged plant parts
• Provide irrigation at critical stages of the crop
• Enhance parasitic activity by avoiding chemical spray, when 1-2 larval parasitoids are observed
• Remove weed plants

Common mechanical practices:

• Handpick the older larvae during early stages
• Collect and destroy plant parts infested with insect pest and diseases
• Handpick the gregarious caterpillars and the cocoons which are found on stem and destroy them in kerosene mixed water.
• Use yellow sticky traps @ 4-5 trap/acre
• Use light trap @ 1/acre and operate between 6 pm and 10 pm
• Install pheromone traps @ 4-5/acre for monitoring adult moths activity (replace the lures with fresh lures after every 2-3 weeks)
• Erecting of bird perches @ 20/acre for encouraging predatory birds such as King crow, common mynah etc.
• Set up bonfire during evening hours at 7-8 pm

Common biological practices:

• Conserve natural enemies through ecological engineering
• Augmentative release of natural enemies

Nutrients

• For achieving higher yields of quality product, generally nutrients may be applied according to the age of plant as mentioned below;

• Apply manures @ 50kg per plant in Dec-Jan every year along with full dose of P and K.
• Nitrogen is applied in 2 splits, first half at 2-3 weeks before flowering and the remaining half a month later.
• The fertilizers should be applied in 20-30 cm deep and 30cms wide trench along the drip line of the tree

Weeds

• Deep hoeing is recommended during the first year to check weed growth. Weeding should be done on regular basis especially around the plants.
• To suppress the weeds between rows, leguminous crops and vegetables can be grown as intercrops in the initial years.
• Use straw or plastic mulches to check the weed growth.
• Use slashing and mowing between the rows to control the weeds

Stem borer

• Follow common cultural, mechanical and biological practices

Cultural control:

• Keep the orchard healthy following good agricultural practices.
• Kill the stem borer larvae by inserting a flexible wire inside the hole and plug the hole with the cotton wick soaked in petrol and seal it with mud.

Mechanical control:

• Prune and burn all attacked shoot and branches during winter.

Shot-hole borer

• Follow common cultural, mechanical and biological practices

Cultural control:

• Attacked shoots should be clipped off and destroyed.
• Clean hole and pour kerosene/petrol/crude oil or formalin into the stem borer hole and subsequently close entrance of the tunnel by plugging with cotton wool and paste the mud.
• Use light trap@1/acre

Leaf roller

• Follow common cultural, mechanical and biological practices

• Follow common cultural, mechanical and biological practices

Cultural control:

• Remove weeds and grasses by ploughing during June-July.
• Plough orchards during summer to expose the eggs to natural enemies and extreme heat.
• Flooding of orchard with water in the month of October kill the eggs.
• Raking of soil under the tree trunks and mixing with some soil dust in the early part of November for control of early instar mealy bug
• Soil solarization with thin polythene sheet for 30-40 days during hot summer
• Fastening of alkathene sheet (400 gauge)/grease band of 25 cm wide afterwards mud plastering of trunk at 30 cm above the ground in the middle of December.
• In July –August destruction of infested fallen leaves with scales

Biological control:

• Raking of soil around tree trunk to expose the eggs to natural enemies and sun, removal of weeds and releasing 10-15 grubs
• Releasing 10-15 grubs of cocinellid predator, C. montrouzieri per tree.

Grey weevil

• Follow common cultural, mechanical and biological practices

Cultural control:

• Collection and destruction of infested and fallen fruits at weekly interval till fruit harvest.
• Ploughing of orchard after harvest to expose hibernating adults, reduce, infestation levels.
• Destroy all left over seeds in the orchard and also in the processing industries.

Walnut weevil

• Follow common cultural, mechanical and biological practices

Leaf spot

• Follow common cultural, mechanical and biological practices

Mechanical control:

• Prune diseased leaves and malformed panicles harbouring the pathogen to reduce primary inoculum load.

San Jose scale, aphids

• Follow common cultural, mechanical and biological practices

Cultural control:

• Grow attractant flowers for natural enemies: viz., sunflower family, carrot family plants, buckwheat etc.

Mechanical control:

• Pruning of infested branches and twigs
• Collection and destruction of pruned infested material.

Biological control:

• Predators such as lady bird beetles - Chilochorus bijugus, Pharosemnus horni, Coccinella septumpunctata, Chlilochorus tristis, Adalia bipunctala, Synharmonia sp. Exochomus quadripustulatus, Hippodamia convergens @ 30-50 adults / infested tree.
• Green lacewings (Chyrsoperla sp.) and Syrphus sp. @10-20 1st instar larvae/tree.
• Parasitiods such as Encarcia perniciosi and Aphytis diaspidis @ 2000 / infested tree after 15 days of insecticidal sprays and 10 days after fungicidal sprays.

Downy leaf spot

• Follow common cultural, mechanical and biological practices

Leaf blotch

• Follow common cultural, mechanical and biological practices

Dieback

• Follow common cultural, mechanical and biological practices

Powdery mildew

• Follow common cultural, mechanical and biological practices

Cultural control:

• Spraying at full bloom needs to be avoided.

Mechanical control:

• Prune diseased leaves and malformed panicles harbouring the pathogen to reduce primary inoculum load

Walnut blight

• Follow common cultural, mechanical and biological practices

Anthracnose

Cultural control:

• Removing leaf debris from around plants
• Avoiding wetting foliage when irrigating.
• Spacing trees adequately to increase air circulation and applications of nitrogen fertilizer in Spring to delay leaf maturity and reduce the development of lesions.

Phytophthora root and crown rot

Cultural control:

• Planting trees in well-draining soils
• Drainage can be improved by levelling soil or installing drainage systems
• Avoid wetting tree trunks when irrigating ensure graft union is several centimeters above the soil line when planting trees.

Armillaria root rot (Oak root fungus)

Cultural control:

• Diseased or dead plants should be uprooted and removed.
• Planting resistant rootstocks is the most effective method

Crown gall

Cultural control:

• Plant disease-free nursery stock.
• Plant trees in well-draining soils.
• avoid wounding the plants

Walnut canker

• Follow common cultural, mechanical and biological practices

Reproductive stage

Nutrient

• Nitrogen is applied in 2 parts, first half at 2 weeks before flowering and the remaining half in two splits at 3 weeks after fruit set and during early July.
• The band application of nitrogenous fertilizers should be preferred over broadcasting.
• Under rainfed conditions, apply N through 1 or 2 foliar sprays of urea (0.5%) after fruit set.
• Apply recommended micronutrients, if symptoms are observed.
• Fruits are deformed under boron deficiency. To avoid boron deficiency, apply H₂BO₃ (0.1%) as foliar spray.

Weed

• Remove weeds around the plants/trees.
• Use straw or plastic Mulch to avoid weed growth and to maintain soil moisture for longer period.
• Mulching tree basins with 10-15 cm thick dry grass also checks weed growth. During the initial 2-4 years, pea, bean, soybean, and cowpea enrich the soil and give economic returns also.

Stem borer

• Same as in vegetative stage

Codling moth

• Follow common cultural, mechanical and biological practices

Cultural control:

• Apart from aforesaid practices, regular monitoring is mandatory for moths,
• For codling moth: Use synthetic codling month for mating disruption at a height of 6-8 feet or Dispensers should be deployed within 1 meter of the top of the canopy prior to spring emergence during late May to 3rd week of July

San Jose scale, aphids

• Same as in planting and vegetative stages

Downy leaf

• Same as in vegetative stages

Spot, Leaf blotch, Dieback, Powdery mildew, Walnut blight, Anthracnose, Phytophthora root and crown rot,