Managing scale insect menace in ginger

Ginger is a subtropical shade loving plant.

The economic part of the plant namely the underground rhizome is often
attacked by scale insect, Aspidiella hartii, both in field and in
storage condition.
The minute crawling nymphs infest near the growing buds and suck the
sap. It results in shrivelling and drying of the rhizomes. The plants
are devitalized and get withered. The rhizomes fail to germinate.

Pest biology
The adult scale insect is circular in shape, light brownish to grey in
colour and about 1mm in diameter.
It reproduces without fertilization laying its young ones directly.
About one hundred nymphs are laid by a single female. The life span is
around one month. The insect multiplies rapidly on stored ginger.
Selection of healthy rhizomes free from scale infestation prevents the
insect spreading to new areas. Avoid water stagnation in the field.
Severely infested rhizomes are to be discarded before storage of
rhizomes.
Soak the rhizome seeds in 0.075 per cent quinalphos for 20-30 minutes
before storing and sowing. Drench the soil with a systemic insecticide
such as dimethoate 30 EC at 2ml/lit of water.

Rhizome treatment
To ensure seed material free from scale infestation, the rhizomes must
be treated with 0.05 per cent phosalone, methamidophos, dichlorvos or
monocrotophos.
The treated rhizomes must be kept at least for a week before planting
to get the maximum effect of the toxicants.
The scale infested rhizomes are to be dipped in the insecticidal
solution for 15 minutes, air dried and can be stored on sand.

Storing method
Storing of rhizomes in dried leaves of Strychnos nux-vomica also helps
in keeping the rhizomes free of scale infestation.
Two species of parasitic wasps and one species of a predatory mite
keep the population of ginger scale insect under biological control.

J. JAYARAJ & M. ANANTHAN

HORTICULTURAL RESEARCH STATION, THADIYANKUDISAI PERUMPARAI, DINDIGUL,

Papaya mealy bug – a new threat to sericulture

Papaya mealy bug – a new threat to sericulture

Papaya mealy bug is a polyphagous sucking insect pest and has been recorded on more than sixty host plants in India.

But its serious attack was recorded only in a few economically important crops such as papaya, mango, pomegranate, citrus, beans, tomato, potato, pepper and cotton. In other plants it exists as a minor pest.

However sudden outbreak of any minor pest is common owing to various reasons.

The recent trend in the population built-up of papaya mealy bug on mulberry, the sole food plant of silkworm, indicates its emerging pest status especially in South India where mulberry is cultivated intensively.

Infestation

Papaya mealy bug infestation is typically observed as clusters of cotton like masses on tender stem and veins of mulberry leaves as the insect secretes a white waxy coat over its body.

The adult female lays 100-600 eggs which hatch into nymphs in about ten days. The nymphs crawl actively to search for feeding sites and settle in clusters on leaves and stems.

One generation

The pest completes one generation in a month. The symptoms appear on the leaves as chlorosis (yellowing), deformation and premature drop. Hence, feeding with papaya mealy bug infested mulberry leaves adversely affects the growth of silkworm and silk production.

Cultural method

Planting of highly susceptible host plants such as papaya or hibiscus in the vicinity of mulberry garden should be avoided.

Plugging of the infested twigs and leaves and their burning during early stage of infestation is the best method of eradication of the pest.

Indiscriminate use of insecticides in mulberry fields should also be avoided as they induce resistance in the pests and destroy its natural enemy population.

Biological control

Release of Cryptolaemus montrouzieri, an effective predatory ladybird beetle at 125 adults per acre twice a year at the interval of six months keeps the pest population suppressed.

Spraying dimethoate (0.05 per cent) controls the pest effectively. Leaves can be fed to silkworms 15 days after spraying the insecticide.

N.Sakthivel

Regional Sericultural

Research Station

Central Silk Board, Salem

Tamil Nadu: 636 003

Integrated Pest Management in Rice

Area coverage of rice is highest in West Bengal (in comparison to any
other crops) and naturally a considerable amount of pesticide is used
to protect the crop from insect and diseases. It is more so for the
boro (winter season) rice which provides higher productivity. In most
of the cases pesticide application is ritualistic and results in
pesticide resistance or pests, environmental pollution and residue
problems. Integrated approach of pest is expected to spell definite
positive results considering the area coverage of rice in the state.
At the same time, complete switch off of pesticide application may not
sound promising in near future. An integrated approach to cope up with
the insect pest problem in rice is, hence, a need of the hour.

1.Selection of resistance varieties
2.Seed treatment with Carbendazim 50 WP (2 g/kg of seed ) and/or
Streptomycin (1g/10 L of water or 1g/6.5 kg of seed)
3.Application of Carbofuran 3G (4.5 kg a.i./bigha) or Phorate 10G (1.6
kg a.i./bigha) in the nursery 7-8 days before sowing.
4.Timely transplanting in larger area at a time.
5.Split application of nitrogen, application of micronutrient.
6.Green manuring; application of organic manure.
7.Removal of weeds from the main field and bunds (bio-physical
boundary of the field).
8.Removal of seedling tip before transplanting.
9.Pheromone traps against stem borer.
10.Gap of 2 rows after each 8-10 rows of seedlings to control Brown
Plant Hopper.
11.Application of neem based pesticides like neem oil/extract.
12.Avoiding pesticide application during the early growth stage of the
plant.
13.Recommended chemicals in extreme cases –
Rice stem borer -
Chloropyriphos (1.5 ml/L of water)
Cartap hydrochloride (1 ml/L of water)
BPH-
Imidachlorpid (1 ml/7.5 L of water)
Thiomethaxom (1 ml/L of water)
Ear cutting Caterpillar -
Profenophos (1.5 ml/L of water)
Cartap hydrochloride (1 ml/L of water)
Blast-
Propiconazole (1 ml/L of water)
Tricyclazole (0.6 g/L of water)
Sheath Blight-
Validamycin (2.5 ml/L of water)
Hexaconazole (2 ml/L of water)

It has been found that the following varieties have considerable
resistance against specific pests.

Rice stem borer - Ratna, Shashyashree, Bikash
BPH - Chaitanya, Pratibha, Manas Sarovar, Reshmi
Blast- Rasi, IR-36, Parijat, Shashyashree
Sheath blight- Pankaj, Swarna, Manas Sarovar

Pests & Diseases

Role of seed treatment in insect pest management

Role of seed treatment in insect pest management

Seed treatment is an application of chemicals to the seeds either at
the time of sowing or before sowing which is an alternative to
traditional foliar or soil treatment.

Efficient function
Application of insecticides to seeds before or at the time of sowing
offers the most effective means of protecting the germinating seed or
seedling.
The chemical insecticide is absorbed by the plant tissue and
transported in the sap through the entire plant through the vascular
system, right up to the top leaf.

Natural enemies
The pest ingests the chemical compounds along with the plant juice
that is lethal for them.
Natural enemy population such as coccinellids, spiders and chrysoperla
remain unharmed.
The efficacy of seed treatment depends upon a mulltitude of
interacting factors such as seed type, chemical formulation,
compatibility of materials, adjuvants and species of insects etc. Seed
treatment with lower doses of imidacloprid, at 5g/kg seed was found
effective in controlling jassids up to 60 days after emergence of crop
and higher seed cotton yield.

Treatment method
Treatment with marshal 25 DS at 80g/kg of seeds has recorded least
population of sucking pests and resulted in higher yield of sunflower.
Acetamiprid 20 SP at dosage of 25g a i/kg of seed protects cotton crop
up to 35 days against pests.
Seed treatment of sorghum with imidacloprid 70 WS at 15g/kg seeds or
thiamethoxam 70 WS at 10g/kg followed by foliar sprays after 30 days
with imidacloprid 17.8 SL at 0.01 per cent or thiamethoxam 25 WG at
0.01 per cent were found highly effective for the management of shoot
fly and stem borer.

Sharanabasappa
D. Satish
& Satyanarayan

Regional Agricultural Research Station, Raichur
& Department of Genetics and Plant breeding
College of Agriculture
UAS Dharwad