Mites,Slug,Snail_Infesting agricultural crops.pdf

Order : Trombidiformes (Acarina) Class : Arachnida
Mites normally feed on the undersurface of the leaves but the symptoms are more easily seen on the uppersurface.
Tetranychids produce blotching (Spots) on the leaf-surface.
Tarsonemids and Eriophyids produce distortion (twist), puckering (Folds) or stunting (Short) of leaves.
Eriophyids produce distinct galls or blisters (fluid-filled sac in the outer layer)

1. Mites
Slugs and Snails
By
Dr. U. Pirithiraj, P.hD.
Assistant Professor (Entomology)
JSACAT
Affiliated to Tamil Nadu Agricultural University

2. Mites
•Order:Trombidiformes(Acarina)Class:Arachnida
•Mitesnormallyfeedontheundersurfaceoftheleavesbut
thesymptomsaremoreeasilyseenontheuppersurface.
•Tetranychidsproduceblotching(Spots)ontheleaf-
surface.
•TarsonemidsandEriophyidsproducedistortion(twist),
puckering(Folds)orstunting(Short)ofleaves.
•Eriophyidsproducedistinctgallsorblisters(fluid-filled
sacintheouterlayer)
Dr. U. Pirithiraj, P.hD. (Entomology)

3. Family:Tetranychidae
Tetranychuscinnabarinus,T.ludeni,T.urticae
Thisspecieshasaworld-widedistribution.Its
infestationrecordedoncastor,pulses,groundnut,daincha,
sesbania.Brinjal,cottonandbhendiaretheworstsufferers.
Symptomofdamage
Undersurfaceoftheleavesgetcoveredwithstrands
ofwebbingwhichaffectphotosynthesisandsotheyield.
Chloroticspotscoalesceintopaleorsilverypatches.
Growth,floweringandfruitsettingintheplantsare
greatlyaffected.Bothnymphsandadultscausethedamage.
Tetranychusurticae
Dr. U. Pirithiraj, P.hD. (Entomology)

4. Oligonychusoryzae
Oligonychusindicus
Itisaseriouspestofsorghum,maize,sugarcaneandsome
cereals.
Symptomofdamage
Whiteorredpatchesonthelowersurfaceofleavesofsorghum
andsugarcane.Bothnymphsandadultscausethedamage.
Oligonychusoryzae
Itinfestsrice.Whitespotsonlowersurfaceofleaveswhich
coalesceleadingtodevelopmentofwhiteorsilverypatches.Itis
severeduringsummer.
Dr. U. Pirithiraj, P.hD. (Entomology)

5. Family: Tarsonemidae
Polyphagotarsonemuslatus (yellow mite, broad mite,
chillimuranaimite)
These are pests of chilli, cowpea, greengram,
horsegram, sesamum, lablab, jute and cotton.
Symptom of damage
Sudden curling and crinkling of leaves followed by
development of blister patches. Severe stunting of
growth and death of plants.
Polyphagotarsonemuslatus
Dr. U. Pirithiraj, P.hD. (Entomology)

6. Panicle rice mite,Steneotarsonemus spinki,
Tarsonemidae, Acarina
Mitesfoundinbetweenstemandleafsheath
Desapthesheathinassociationwithfungus
(Sarocladiumoryzae)
Dr. U. Pirithiraj, P.hD. (Entomology)
Steneotarsonemus spinki

7. FamilyEriophyidae
Aceriacajani
Itisavectorofsterilitymosaicof
pigeonpea.
Aceriasorghii
Leafcrinkling,generalchlorosis
andchokingofterminalleaves.
Hostplantissorghum.
Dr. U. Pirithiraj, P.hD. (Entomology)

8. Management
•Spray wettablesulphur50 WP 2g/lit or dicofol18.5 EC 2.5 ml/lit
•The mite develops resistance within 2–3 years, so repeated use of
acaricidesshould be avoided to reduce resistance.
•Carbaryland pyrethroidsshould not be used as they increase the
pest incidence.
•Sulphur based insecticides must not be used in cucurbits as they
cause phytotoxic effects.
Dr. U. Pirithiraj, P.hD. (Entomology)

9. Slugs and Snails
Snails differ from slugs in having a spirally coiled shell over their body
They do a lot of damage to vegetables, garden plants, the damage being more serious
in the seedling stage.
Invertebrata
Phylum: Mollusca
Class: Gasteropoda
Dr. U. Pirithiraj, P.hD. (Entomology)

10. Giant African snail -Achantinafulica-damage
plantation crops like arecanut, rubber buds and
coffee
Common garden snails -MacrochlamysindicaGreen house snail -Opeasgracilis
Dr. U. Pirithiraj, P.hD. (Entomology)

11. Common Indian slugs : Limaxsp.,
Laevicaulisalte
Arion sp.
Dr. U. Pirithiraj, P.hD. (Entomology)

12. Management
Cultural
•They can be handpicked and killed.
Chemical
•Metaldehyde(5%)
•Copper sulphatesolution (1%)
Dr. U. Pirithiraj, P.hD. (Entomology)