PADDY LEAF FOLDER

LEAF FOLDER (OR) LEAF ROLLER IN PADDY

1. Name of Pest: Leaf folder (or) leaf roller (Cnaphalocrocis medinalis).It is a Monophagous pest( feeding on a single kind of plant or animal)

2.Host plants: Rice,Wheat,Sorghum,Indian goosegrass(Eleusine indica)  etc.

3.When it occurs:

   ➥ Observed from early transplanting to boot leaf stage. 

   ➥ Mostly occurred from Tillering to Flowering Stage (May to October) . 

  ➥ more abundant during the rainy seasons. When Optimum Temperature :25-29°C High humidity (80 % ) and shady areas of the field.

   ➥ use of Excessive fertilizer helps for rapid multiplication of the insect. 

 ➥ Leaf folders infest at reproductive phase, the damage can be economically important. High feeding damage on the flag leaves can cause yield loss.

4. How to identify insect pest: 

• Adult:Adult moth golden-yellow or orange-brown zig-zag lines on the wings.The Adult moth length of our fingernail (2 cm). dark-coloured inner and Middle band short and incomplete. 

• Eggs: Eggs are creamy white.which are 0.90 mm long and 0.39 mm wide.oval in shape. Incubation period:4-7 days. 

• Larvae: Larvae are pale yellowish to green in colour. larval period is 15-27 days.Total life cycle is 26-42 days.

5. What does it do :

Eggs are usually laid at the tip of the leaf. caterpillars fold a rice leaf around themselves and attach the leaf margins together with silk strands.Leaves fold longitudinally and larvae remains inside. Larva scrapes the green tissues of the leaves, becomes white and dry .They feed inside the folded leaf.

5.Damage Symptoms:

• The leaves of the plant are seen folded, rolled and often webbed together with white patches on them indicating the areas fed by caterpillar.

• When such folded leaves are opened up, larvae can be seen.

• During severe infestation the whole field exhibits whitish scorched appearance.

• The larvae feed by scraping the green mesophyll resulting in linear pale white stripe damage.

• In cases of severe infestation, the leaf margins and tips are dried up entirely and the crop gives a whitish appearance

🔺Similar symptoms:

Folded leaves are also similar symptoms of rice skippers and green semilooper. The whitish streaks are comparable to leaves damaged by rice whorl maggot and thrips.

6. Management Practice:

     [A] Cultural Methods:

• Use resistant varieties.like, PNR-519, IR-50, Jolaprava, Jitendra,sudhir ,Cauvery, TKM 6, TKM 12, ADT 46,TPS 2, TPS 3, ADT 44, PY 4, Kairali,Ahalya,Reshmi (PTB 44), Neeraja(PTB 47) and Deepthi.

• Keep the bunds clean by trimming them and remove the grassy weeds.

• Avoid use of excessive nitrogenous fertilizers.

• Split the fertilizer application during the growing season and apply nitrogenous fertilizer judiciously.

• Avoid use of Carbofuran (or) Phorate granules to control resurgence of pests.

• Clipping of the affected leaves.

• Use of rope to dislodge the leaf feeding larvae of leaf folders.

• Open up the leaf folds with the help of a thorny twig.

• Flood and plow field after harvesting if possible.

• Remove grassy weeds to prevent the buildup of rice leaf folders which act as the alternative hosts.

• Adjust the time of planting to avoid peak time of leaf roller. Cover the seedling nursery with nylon film or insect net after planting, preventing damage from laying eggs.

     [B] Biological Methods:

• Release the egg cards in the field during morning hours.

• Release the egg parasitoid Trichogramma chilonis at 5 cc/ha on 37, 41 and 51 days after transplanting.

• Protect natural enemies (frogs, spiders and other beneficial insects), rear ducks in the rice field to control leaf rollers.

• Avoid spraying of chemicals three days before and up to seven days after field release of egg cards.

     [C] Mechanical and Physical Methods:(Trap Methods):

• Set up light traps to attract and kill the moths. Set up light trap one for at least 5 ha.

• Monitor through pheromone traps (@ 10 to 12 no per ha (3-4 no per Acre) for timely control measures. Change the lure at 15-20 days intervals.

• Set up bird perches @ 40 to 50 per ha(5 no per Acre)  at vegetative phase of the crop.

     [D] Chemical Methods: Spray any one of the following insecticides: water:ha:500 Lit.

• Azadirachtin 0.03% @ 3 ml per Lit. of water(1000 ml/ha).

• Chlorpyriphos 20 % EC @ 2.5 ML/Lit. Of water (1250 ml/ha )

• Acephate 75 % SP @ 0.75 gm per Lit. of water.(666-1000 ml/ha).

• Flubendiamide 39.35% SC @ 1ml per 5 Lit. of water( 50 gm per ha)

• Flubendiamide 20% WG@ 1 gm per 4 Lit. of water(125-250 g/ha)

• Thiamethoxam 25% WG@ 1 gm per 2 Lit. of water 100 kg/ha.

• Indoxacarb 15.8 EC @ 1.4 ml per 2 lit of water.

• Fipronil 5 % E.C @ 1 ml per Lit. of water or Fipronil 80%WG @ 50-60 gm per ha.( 20-25 gm per Acre).

• Cartap Hydrochloride 50 % SP @ 1-2 gm/lit.of water(1000 g/ha)

• Chlorantraniliprole 18.5% SC@ 1ml/ 3 lit.of water 150 g/ha or Chlorantraniliprole 0.4% G @ 10 kg/ha.( 4 kg per Acre).

• Carbosulfan 6% G @ 5-6 kg per acre (16.7 kg/ha)

• Carbaryl 50 % WP @ 2.5 gm/lit.of water (1.0 kg/ha)

• Phosphamidon 40% SL @ 2.5 ml per Lit. of water.(1250 ml per ha.)