Tobacco leaf-eating caterpillar ( text from http://www.indiaagronet.com)

Tobacco leaf-eating caterpillar

Spodoptera litura F.
Family:- Noctuide
Order:- Lepidoptera

Marks of identification: - The moths are medium sized and stout bodied, with front wings pale Grey to dark brown in colour having wavy marking and whitish hind wings. The caterpillars are pale greenish-brown and smooth, with dark markings and a prothoracic plate and are about 37.5mm long when full-grown.

Nature of damage; - The caterpillars, when young, feed gregarously on tender leaves and juicy stems at become isolated at the later stages of growth.

Host plants: - Tobacco, peas, brinjal, castor, banana, agathi are the main hosts.

Life history; - Numerous eggs are laid in masses covered with brown hairs on tender leaves and they hatch in a period of four to five days. The caterpillars, which are darkish in appearance, on hatching start feeding on the soft green layers of leaves gregariously during the night, both in seedbeds and planted fields. They become pupate in rough earthen cocoons. Their pupal period lasts from nine to fourteen days and the total period of their lifecycle is 30 to 40 days.

Control measures; - Preventive measures such as collection and destruction of eggs masses and caterpillars and thorough ploughing after the harvest of the crop to expose pupae may be launched with a fair degree of effectiveness. At the early stage of infestation dusting with 10% carbayl at 20-25 kg/ha controls the pest satisfactory. When the caterpillars are about to pupate it is better to collect and destroy them on large scale.

Leaf spot in Turmeric - Text from http://www.spices.res.in

Leaf spot
The disease is caused by Colletotrichum capsici.

Symptoms
* It appears as brown spots of various sizes on the upper surface
of the young leaves.The spots are irregular in shape, whitish or
grayish in the centre.
* Later two or more spots may coalesce and form an irregular patch
covering almost the whole leaf.
* The affected leaves eventually dry up.
* The rhizomes do not develop well.

Management
* The disease can be controlled by spraying the plants with zineb
0.3% or Bordeaux mixture 1%.

Rhizome Rot ( Phytium graminicolum) in Turmeric - Text from http://www.spices.res.in

From these photographs, you can see various stages of Rhizome rot in Turmeric and ultimate damage too.

Symptoms

• Starting from the margins the leaves get dried up, collar region of pseudostem becomes soft and water-soaked and plants collapse.
• The rhizomes decay as a result of the attack of the fungus.

Control

• Seed Material should be selected from disease free areas.
• Avoid water Stagnation in the field. Light soil may be preferred and drainage facility to be ensured.
• Grow tolerant varieties like Suguna and Sudarshan.
• Crop rotation to be followed.
• Deep ploughing to be given in Summer. Planting to be done in Ridge and furrow method.
• Remove diseased plants and the soil around plants to be drenced with Mancozeb (3gm/lit) or 3gm Ridomil M.Z.
• Spray on the crop Mancozeb (2.5g/lit) or Carbendazim (1g/lit) +1ml Sandovit.
• Seed treatment is a must. Keep Rhizomes in 3gm Mancozeb or 1gm Carbendazim or 3gm Ridomil M.Z or 2.5 gm Metalaxyl mixed in one litre of water solution for one hour and shade dry before planting.

Control of leaf miner menace in watermelon

Control of leaf miner menace in watermelon

Watermelon crop is attacked by many insect pests, of which leaf miner, assumes significance as it causes greater damage.

The larvae feed on the leaves by mining into them. Smaller leaves with limited feeding space are characterised by a secondary blotch.

Damage caused by a single larva is minimal; however, when the population is heavy they are capable of destroying more leaves and affect the plant growth.

Larvae are easily visible. Yellow and white to brown tunnels or blotches are noticed between the upper and lower surface of leaves. These tunnels spread all over the leaf making loops. Severely affected leaves curl, turn brown and die.

Pest biology

Eggs are oval in shape and creamy white in colour and are laid singly in punctures on the epidermis of the leaf. Entire larval period lasts for 7-9 days.

Pupae are yellowish brown in colour and distinctly segmented. Pupae are oval shaped with narrow ends. Adults are small grey coloured flies with black and yellow markings and live for about 10-20 days depending on the environmental conditions.

Management

— Collect and destroy damaged leaves along with larvae.

— Maintain the field and bunds free from weeds.

— Install yellow sticky traps to attract and kill the adults. These should be placed in and around the field at about 10 cm above the foliage. Replace the trap at least once a week.

— Avoid water stress in irrigated crop. Set up light traps to monitor and attract the leaf miner moths.

— Dusting leaves with phosalone 4D at 25 kg/ha or Carbaryl 10D at 25 kg/ha will be effective.

V. Radhakrishnan

& K. Ramaraju

Department of Agricultural Entomology

Tamil Nadu Agricultural University, Coimbatore

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