Pear is the temperate fruit grown mainly in temperate regions or in regions of higher altitudes.
Here, Pest infesting pear fruits and its management stratergies are dealt here
2. INTRODUCTION
Pyrus communis is a deciduous small to medium-sized
tree to 10 m tall.
The pear belongs to the family Rosaceae.
Pear is grown in temperate and subtropical condition
because of its wider climatic and soil adaptation.
Native :Western Europe and North Africa.
China is the leading producing country of pears in the
world recording a production of 17.3 million metric tons
in 2013.
The US is the second largest pears producer and recorded
0.795 million metric tons during the same period.
While India production is 306 metric tonnes in 2018.
3. Pears are self-sterile and need more than one variety
planted within 12 or 15 m of each other in order to
cross-pollinate.
The important pollinators are honeybees.
USES
The fruit is eaten fresh, in fruit salads, or more rarely,
canned. Sometimes, they are dried or candied.
They are also used in jams and jellies.
Its wood is brown-reddish, compacts, with several
applications such as in furniture.
The antibiotic-like substance (Phloretin) found in apple
bark is present in bark of pear.
While in Europe, the alcoholic cider "Perry" is made
from the pear.
4. Major pest
Borer Insect
Codling moth Cydia pomonella Tortricidae Lepidoptera
Stem borer Aeolesthes sarta Cerambycidae Coleoptera
Sucking Insects
San Jose-Scale Quadraspidiotus perniciosus
(Comstock)
Diaspididae Hemiptera
Pear psylla Cacopsylla pyricola Psyllidae Hemiptera
Green peach aphis Myzus persicae Aphididae Hemiptera
Thrips Taeniothrips sp Thripidae Thysanoptera
Mites Panonychus ulmi Tetranychidae Arachnida
6. They are major pests to agricultural crops, mainly fruits such
as apples and pears.
Because the larvae are not able to feed on leaves, they are
highly dependent on fruits as a food source and thus have a
significant impact on crops.
The caterpillars bore into fruit and stop it from growing,
which leads to premature ripening.
Codling moth
Cydia pomonella ;Tortricidae ;Lepidoptera
7. BIOLOGY
Egg :
Eggs are deposited singly on pears and leaves (30 to 70).
Each egg is about the size of a pin head and is
translucent, gradually darkening as the egg nears hatching.
Eggs hatch in six to 14 days, depending on temperature.
Larva:
Full grown larva pinkish or creamy white with brown head
and pupates in the soil litter.
Codling moth overwinters as full-grown larvae within
thick, silken cocoons under loose scales of bark and in
soil or debris around the base of the tree.
8. Pupa:
After completing development they leave the fruit
and drop from the trees and pupate in the soil or
on debris under the tree.
Some crawl back up the tree to pupate in bark
crevices.
Adult:
Adult forewings are dark grayish with waxy lines
with a copper colored eye like circle toward
margin.
10. Symptoms of damage
It is a direct pest and hence causes severe damage to the fruit.
Neonate larva enters the fruit through calyx and feeds on
seed.
Infested fruits lose their shape and fall prematurely.
30 to 70 per cent pear fruits are rendered unmarketable.
11. Management
Mechanical Method :
All loose barks of trees scrapped off to remove
overwintering sites for the caterpillar.
Fallen fruits should be collected and buried deep in the
soil.
Bands of sacking(Gunny bags) or corrugated cardboard
can be tied round the tree trunks by late july till the end of
october to provide alternative over wintering sites for the
caterpillars.
These bands should be removed during the first week of
November and either burnt or immersed in a pail of
boiling water or kerosined water.
12. Biological Method :
Parasitoids: Trichogramma embryophagum,at the rate of 20000
adults per 50 trees.
Predators:Birds (grey tit, Parus major and Passer domesticus) play
an important role in pest suppression.
Chemical Method :
Well timed sprays of relatively safer insecticides are effective in
controlling Codling moth.Spray timings should be related to
moth catches in sex pheromone traps.
The pesticides that can be used are
Chlorpyriphos 0.02% @ 2ml/lit
Fenitrohion 0.02% @ 1 ml/lit
Diazinon 0.045% @ 1.5ml/lit
Malathion 0.05% @ 2ml/lit
13. Its origin is believed to be Pakistan and Western India.
Aeolesthes sarta is a polyphagous insect.
Its preferred hosts include English walnut,
Apple,Willow, and Elm.
However it may also attack Mulberry,
Prunus (stone fruits), Pears and Oaks.
Stem borer
Aeolesthes sarta (Coleoptera:Cerambycidae)
14. BIOLOGY
Egg:
Female lays egg inside cavity on a shoot.
Eggs are very difficult to see and
laid singly on the trunk of the tree.
Larva:
Larvae are dirty white with a reddish-brown head
and thoracic shield.
Grub start feeding by boring inside the stem.
Grub longevity 2 years,remains quiescent
during winter.
15. Pupa:
Pupation takes place inside a tunnel made
in the woody tissue.
Pupae are small, yellow-brown partially
protruding from the adult exit holes in the
trunk.
Adult:
Adult beetles 35-50 mm long and grey in
colour having long antennae.
17. Symptoms of damage
Caused by grub and adult and the grub is more destructive.
Grub makes a tunnel and reaches close to trunk of tree.
Vitality and productivity of plant is greatly impaired.
18. MANAGEMENT
Clear the holes with flexible wire and then insert 0.5gm
Paradichlorobenzene(PDCB) in the hole and plug it
with puddling material or insert cotton wick soaked with
Petrol or Methyl parathion (1ml/lit) or Dichlorvos (0.15
ml/lit of water and plug the hole.
Swabbing the infested branches and trunk with
10%carbaryl dust and soil in the ratio of 1:6 mixed with
Rice or Wheat straw.
19. San Jose-Scale
Quadraspidiotus perniciosus ; Diaspididae ;Hemiptera
This species originated in Siberia, North East China and the
Northern part of the Korean peninsula.
San Jose scale is an extremely important pest of apples, pears,
peaches, and plums.
The presence of reddish blemishes on fruit at harvest indicates
potentially damaging numbers on the trees.
Left uncontrolled, San Jose scale can kill the entire tree in a
couple years.
20. BIOLOGY
Egg :
Eggs are minute, oval, and creamy white to yellow.
Each female lay birth to 200-400 eggs.
Nymph:
Eggs immediately hatch to colourless nymphs that emerge
from under the edge of the scale covering.
These tiny yellow crawlers wander in a random fashion until
they find a suitable place to settle.
Immediately upon settling, the crawlers insert their mouthparts
into the host plant and begin feeding and secreting a white
waxy material (white cap stage); eventually the waxy covering
turns black and is known as the black cap stage.
21. Adult:
Immature male and female scales are indistinguishable until the
first molt.
Male :
At this time, the male scale covering begins to elongate, while
the females remain circular.
Males molt a total of four times. Following the final molt,
adult male scales emerge from the scale covering as tiny,
yellow winged insects.
Female :
Female insect body covered with grey scales. Yellow lemon
coloured female is visible when covering is lifted.
22. It takes 25 days for males to mature and 31 days for females.
Five to six generations in a year
23. Symptoms of damage
Nymph and female scales attack all above ground parts.
Feeding site turns into a characteristic purplish red colour.
Initially growth of plant is checked but as scale increases in
number plant may die.
Fruits will have distinct “measles” spots on the surface.
24. Managaement:
Prune the infested plant parts and destroy.
Fumigate nursery stock with HCN gas or Methyl bromide.
Encourage the activity of parasitoids:
Prospaltella perniciosi and Aspidiotophagus sp
Field release of coccinellid, Chilocorus circumdatus predator.
Winter spray with diesel oil emulsion at 8-12 l/ tree ( diesel oil 4.5 l,
soap 1 kg, water 54 -72 l).
Summer spray with Phosalone 50 EC 0.05% or Fenitrothion
50 EC 0.05%
25. Psylla pyri, commonly known as the pear psylla or pear
psyllid.
Originating in Europe and Asia.
It is a pest of pear trees, sucking the sap, damaging the
foliage, flowers and fruit and diminishing the crop.
Pear psylla
Cacopsylla pyricola ; Psyllidae ;Hemiptera
One of the most serious insect pest of
pears because of its ability to
develop Resistance to insecticides and to
vector the pathogen that causes Pear
decline.
26. BIOLOGY
Egg:
Eggs are minute, oval, and creamy white to
yellow.
Eggs are deposited along mid-veins and
petioles of developing leaves and on stems and
sepals of blossoms.
Nymph:
Early instars are about 1.6 mm long and light
yellow; later instars are dark green to dark
brown with wing pads and two conspicuous
red eyes.
27.
28. Adult:
Adults are 4 mm long and red-brown to black in colour.
It resembles miniature cicada with wings held roof-like over the
abdomen.
Adults leave the pear trees in Oct.-Nov. for wintering sites and
return about 6 weeks before bloom.
29. Damage symptoms
Nymphs and adults suck sap primarily from the tender
foliage of the new shoots and water sprouts.
Feeding by nymphs produces a large amount of
honeydew, which makes the tree sticky and promotes the
growth of sooty mold (black fungus).
The honeydew can run onto fruit causing dark russet
blotches or streaks resulting in unmarketable fruit.
30. MANAGEMENT
Cultural Methods :
First minimize heavy pruning, which encourages the
proliferation of terminal shoot growth which provides
more feeding sites for the psylla.
Remove suckers from the interior of the trees, which
removes psylla eggs and nymphs and increases spray
coverage.
Biological control:
A number of natural enemies attack psylla, including
parasitic wasps, adults and larvae of lady beetles,
lacewings, and earwigs, as well as predacious plant bugs
and minute pirate bugs.
31. CHEMICAL METHOD
Dormant-season spray:
Mineral oil
Lime sulfur mixed with superior-type oil.
Use enough water to cover all of the tree thoroughly
including small limbs and shoots.
The chemicals commonly utilized are
Phosalone 35 EC (Zolone)
Abamectin 1.8 EC (Vertimec)
Diflubenzuron 48 SC (Dimilin)
Teflubenzuron 15 SC (Nomolt)
Flufenoxuron 5 EC (Cascade )
32. Several aphid species occasionally attack pears; the most
common are green peach aphid, cotton aphid (also known as
melon aphid), and bean aphid (also known as dock aphid).
These aphids overwinter as adults on various weeds and field
crops in or outside the orchards.
Usually after pear bloom, when trees are
growing rapidly, these aphids appear on foliage
and shoots and establishing colonies.
Green peach aphid
Myzus persicae ; Aphididae ;Hemiptera
33. BIOLOGY
Egg :
The eggs measure about 0.6 mm long and 0.3 mm
wide, and are elliptical in shape.
Eggs initially are yellow or green, but soon turn black.
Nymphs :
Nymphs initially are greenish, but soon turn yellowish,
greatly resembling viviparous (parthenogenetic,
nymph-producing) adults.
There are four instars, with the duration of each
averaging 2.0, 2.1, 2.3, and 2.0 days respectively.
34. Adult:
Winged aphids have a black head and thorax, and a
yellowish green abdomen with a large dark patch
dorsally. They measure 1.8 to 2.1 mm in length.
When aphid densities increase winged forms are
produced, which then disperse to summer hosts.
35. The average length of life is about 23 days.
The maximum number of generations to be 20 to 21.
36. Damage symptoms
Green peach aphids can attain very high densities on
young plant tissue, causing water stress, wilting, and
reduced growth rate of the plant.
Blemishes to the plant tissue, usually in the form of
yellow spots, may result from aphid feeding.
37. MANAGEMENT
Remove and destroy the damaged plant parts along with
nymphs and adults.
Natural Enemies :
Parasitoid : Aphelinus mali
Predators : Coccinella septumpunctata , Syrphid fly,
Lygaeid bug, Coccinellid, Lacewing.
Chemicals:
Spray dimethoate 0.03% or methyl demeton 0.025% @
2 ml/lit.
38. The pear thrips has been considered primarily a threat to
fruit growers, but for many years now has been causing
damage to sugar maple, red maple, and beech.
Other recorded hosts include pear, apple, apricot,
cherry, grape, peach, plum and willow.
The pear thrips is an imported species that was first
found in California in 1904.
Most thrips feed on plants, attacking flowers, leaves,
buds and fruits.
Thrips
Taeniothrips sp, Thripidae ; Thysanoptera
39. BIOLOGY
Egg:
The eggs are deposited within plant tissues singly.
Nymph and pupa:
Larvae have two stages, which feed on plant
tissues.
The second instar larvae, when mature, fall to
ground, where they molt to prepupae and pupate
in the soil.
Adult :
The pear thrips adult is dark brown and only about
1/20 of an inch in length.
Adult thrips are slender bodied with four narrow,
feather-like wings.
40.
41. Damage:
Adults enter the bud or start feeding on the bud tip, and
gradually work themselves in.
The larvae feed voraciously for about 3 weeks, adding to
the damage already caused by the adults.
Feeding is usually concentrated on flower
parts, which gives the blossom buds a
shriveled, scorched appearance, or causes
them to fall off completely.
42. MANAGEMENT
The damage done by thrips takes place over a short time
span, and insects are concealed in buds for much of that time.
Cultural Methods :
Reduce the stress on susceptible tree species through good
cultural practices including proper pruning, fertilization,
proper mulching and irrigation during dry periods.
Thrips may be reduced by removing as many broadleaf
flowering plants as possible from the vicinity of the trees,
as this provides an alternate host.
43. Biological Method :
Predators:
Antlion, predatory thrips, coccinellids, anthocorids, lygaeids etc.
Chemical Method :
Spray any one of the following insecticides :
Imidacloprid 17.8 % SL 3.0 ml/10 lit.
Dimethoate 30 % EC 1.0 ml/lit.
Fipronil 5 % SC 1.5 ml/lit.
Spinosad 45 % SC 3.2 ml/10 lit.
44. Panonychus ulmi, the European red mite, is
a species of mite which is a major pest of fruit trees.
It has a cosmopolitan distribution and a very wide host
ranges, such as apple, pear, plum, peach, prune and cherry
that it reaches economic importance.
It has a high reproductive rate, a short generation time (21
days at 20 °C) and produces many broods in a year, all of
which contribute to its pest status.
Mites
Panonychus ulmi ;Tetranychidae ; Arachnida
45. BIOLOGY
Egg:
1) Summer egg :
The summer eggs are globular and somewhat
flattened (onion shaped) .
They are bright red to dark orange, and average
0.13 mm in diameter.
2) Overwintering eggs :
The overwintering egg is deeper red and slightly
larger, averaging 0.14 mm.
The egg surface is ridged with the grooves
running toward the top center from which a
slender tapering stalk (0.1 mm) arises.
46. Nymph
Nymphs consist of larva, protonymph and deutonymph.
A quiescent or resting period precedes each molt to the
following stage.
The hatching larva is about 0.2 mm in length, light orange
in color and 6 legged. All subsequent stages have 8 legs.
47. Adult:
The sexes of the adults are readily differentiated.
The female has a globular body which ranges in length from
0.38 to 0.40 mm, is velvety brown to brick red, and has 4
rows of dorsal setae or spines borne on raised white
tubercles.
The male is smaller, 0.26-0.28 mm in length, lighter in color
and has a pointed abdomen and proportionately longer legs.
48. EggNymph
Adult
European red spider mite
Panonychus ulmi
5-15
days
6-15
days
18
days
The average life span is 18 days.
The oviposition period averages 12.5 days with 18.8 eggs
produced per female.
49. Symptoms of damage
The mites feed by puncturing cells of the leaf parenchyma
with their stylets and sucking out their contents.
This causes physiological changes in the leaves, and
photosynthesis, transpiration and nitrogen accummulation
can be severely constrained.
Severe mite injury produces browning and loss of
colour in the leaves i.e. bronzing.
50. Management
Cultural control:
Regular orchard monitoring for pest & defender population.
Plant should neither be forced to drought nor water lodging
conditions.
Biological control:
Predators: Coccinellid, Lacewing, Predatory mite,
predatory thrips, spider etc.
51. Chemical Method
The pest’s larvae and young nymphs are quite susceptible
to pesticides, thus spraying in the spring, as the diapause
eggs are hatching, would give best results.
The pest may be controlled with many acarides, but has
developed much resistance to most pesticides.
Avermectins and propargite provided good mite control in
Syria.
Pyrethroids encourage outbreaks of the European red mite.
Neem oil (2%), NSKE (5%).
52. Cultural Method :
For raising of nurseries, selection should be made which is
free from pest infestation.
Don’t grow the nursery at the same site every year.
Growing of flowering plants especially Marigold and Maize
helps in the conservation of both predators and parasites.
Maintain the vigour of the tree to keep away the shot hole
borers,beetles and other pests.
Reduce the stress on susceptible tree species through good
cultural practices including proper pruning, fertilization,
proper mulching and irrigation during dry periods.
Integrated pest Management
53. Mechanical methods
Remove and destroy dead and dying fruit trees to ward off
borer infestation.
Prune and destroy the scale and borer infested twigs
/branches.
Collect and destroy the fallen fruits.
Clean the stem borer hole with flexible wire and apply the
recommended chemicals.
Install a light trap near the orchard to collect and kill the
beetles in kerosinized water.
Remove suckers from the interior of the trees, which
removes psylla eggs and nymphs and increases spray
coverage.
54. Biological Methods
While planting nursery make use of neem cakes which ward off any
soil pests.
Monitor the incidence of sucking pests like San jose
scale,Mite,Aphid and make release of ,
Predators: Coccinella septempuncta ,Chilocoris sp,Adalia
bipunctata @30-50adults /infected tree.
Green lace wing : Chrysoperla sp and Syrphus sp @ 10-20
larvae/tree.
Parasitoids : Encarsia perniciosi and Ephytis diaspidis
@2000/infested tree atleast 15 days after insecticidal sprays.
55. Chemical Methods
Need based ,judicious and safe application of pesticides
are the most important ones under the IPM program.
Observing ETL and conserving natural biocontrol
potential before deciding in favour of use of chemical
pesticides as a last resort.
Avoid use of Synthetic pyrethroids which may cause
resurgence of sucking pests.
Avoid mixing of two or more insecticides/tank mixing.
Encourage the use of neem based formulations.
Tractor mounted sprayers/Power sprayers for effective
coverage.
56. Description and management strategies of important
pests of pear: A review –Journal of Entomology and
Zoology studies.
Integrated pest management package for Pear –
Directorate of Plant protection,Quarntine and storage.
AESA based IPM Package for Pear –NIPHM,Hyderabad.
References
