Content Reference : CABI/IKSL/HAFRICE/AUG09/1 Important Pests of Paddy (Oryza sativa ) Prepared by Barbara J. Ritchie & David Hunt ,CABI Europe UK Centre Content Reference : CABI/IKSL/HAFRICE/AUG09/1 Rice Leaf Folder Fact Sheet (also known as rice leaf roller, grass leaf roller) Date: 00/00/00 Sign up heading. Content Reference : CABI/IKSL/HAFRICE/AUG09/1 Cultural Control Biological Control Chemical Control • Not to use too much fertilizer • Among the biological con- • Control of leaffolders using chemicals during the early trol agents, there are small • Surrounding grass habitats crop stages is not advis- wasps and crickets that at- able. A general rule-of- should be maintained be- thumb is “spraying insecti- tack the eggs cides for leaffolder control cause these serve as tempo- • The larval and pupa stages in the first 30 days after transplanting (or 40 days are parasitized by many rary reservoirs of natural after sowing) is not needed. species of wasps. Damsel- • Pyrethroids and other enemies like crickets, which broad-spectrum insecti- flies, ants, beetles, wasps, cides can kill the larvae but are egg predators of leaf mermithids, granulosis vi- can put the crop at risk be- cause of the development rus, and nucleopolyhedrosis folders of secondary pests, such virus prefer the larval as the brown plant hopper • • If infestations of the flag stages leaves are extremely high • Spiders and mermithids at- (>50%) during maximum tillering and maturity stage, tack the adults insecticide sprays may be useful Content Reference : CABI/IKSL/HAFRICE/AUG09/1 Rice Stem Borer Fact Sheet (Yellow stem borer (YSB), Scirpophaga incertulas , DarkDark----headedheaded stem borer (DHSB), Chilo polychrysus & Pink stem borer (PSB), Sesamia inferens ) Cultural Control Biological Control Chemical Control • Cultural control measures include • Biological control agents include bra- • Between hatching and penetration into the stem, the larvae are exposed proper timing of planting and synchro- conid, eulophid, mymarid, scelionid, to insecticide sprays for only a few chalcid, pteromalid and trichogram- nous planting. The crops should be hours. In general, systemic insecti- matid wasps that parasitize the eggs cides are more effective against S. harvested at ground level to remove of yellow stem borer. Ants, lady bee- incertulas than non-systemic ones the larvae in stubble. Likewise, stubble tles, staphylinid beetles, gryllid, • The economic threshold for S. incer- tulas is 2 egg masses per 20 hills up and volunteer rice should be removed green meadow grasshopper, and to panicle initiation stage, and 1 egg and destroyed. Ploughing and flooding mirid bug also eat eggs. The larvae mass thereafter (Reissig et al., are parasitized by phorid and 1986). Egg masses may be counted the field can kill larvae and pupae in platystomatid flies, bethylid, braco- on 20 random hills along the diago- the stubbles. At seedbed and trans- nal of the field. When the threshold is nid, elasmid, eulophid, eurytomid and reached, egg masses need to be col- planting, egg masses should be hand- ichneumonid wasps. They are at- lected and reared in vials or jars. If picked and destroyed. The level of irri- tacked by carabid and ladybird bee- more parasitoids emerge than S. in- certulas larvae, then there is no gation water can be raised periodically tles, chloropid fly, gerrid and penta- need to apply insecticide. However, tomid bugs, ants, and mites. Bacteria to submerge the eggs deposited on the if the larvae are more numerous than and fungi also infect the larvae. A the parasitoids then the application lower parts of the plant. Before trans- mermithid nematode also attacks the of insecticide is justified. Light traps planting, the leaf-top can be cut to re- larvae. Chalcid, elasmid and eulophid may be used to catch S. incertulas, the occurrence of which can be used duce carry-over of eggs from the seed- wasps parasitize the pupae. Ants and as a signal to start monitoring for bed to the field. Application of nitrogen earwigs also eat the pupa. Bird, asilid egg masses in the field. However, fly, vespid wasp, dragonflies, damsel- the economic threshold level prac- fertilizer should be split following the flies, and spiders prey upon the ticed in Bangladesh is 3 egg mass recommended rate and time of applica- and/or female moths/m² or 10-15% adults deadhearts (Anon., 1999). tion. Content Reference : CABI/IKSL/HAFRICE/AUG09/1 Brown Plant hopper (BPH), (Nilaparvata lugens) Fact Sheet Cultural Control Biological Control Chemical Control • For example, draining the rice • The common parasites of the • Insecticides from the three ma- eggs are the hymenopteran jor classes (carbamates, or- field for 3-4 days is recom- wasps. Eggs are preyed upon by ganophosphates and synthetic mended during the early stage of mirid bugs and phytoseiid mites. pyrethroids) have been found to Both eggs and nymphs are increase densities of N. lugens infestation. Nitrogen application preyed upon by mirid bugs. after treatment can be split to reduce BPH Nymphs and adults are eaten by • Buprofrezin is an insect growth general predators, particularly regulator active against the buildup. Synchronous planting spiders and coccinellid beetles. BPH nymphal stages but not within 3 weeks of staggering and • Hydrophilid and dytiscid bee- against the egg and adult tles, dragonflies, damselflies, stages. It should be used only maintaining a free-rice period and bugs such as nepid, microv- when the majority of the field could also decrease the build-up eliid, and mesoveliid eat adults population are second or third and nymphs that fall onto the instar. For control of adults and of BPH.... water surface. other insects in rice, BPMC and • There are varieties released by • Fungal pathogens also infect MICP (carbamates) are advised brown planthoppers. due to their lower toxicity to IRRI, which contain genes for • BPH is a secondary problem natural enemies of N. lugens. BPH resistance, like IR26, IR64, due to insecticide spraying for Granular carbofuran (3G) has leaf-feeding insects in the early been indicated to cause resur- IR36, IR56, and IR72. crop stages. To reduce the risk gence although it is commonly . of hopperburn, application of recommended for high infesta- early season insecticide should tions of stem borers. be avoided. .