In southern Asia, Chilo auricilius Dudgeon, Chilo infuscatellus Snellen, Chilo partellus (Swinhoe), Chilo polychrysus (Meyrick), Chilo suppressalis (Walker), Chilo suppressalis simplex (Butler), Chilo sacchariphagus indicus (Kapur), Chilo supermain and Chilo tumidicostalis Hampson are recorded as pests of cereal crops. Chilo partellus causes severe losses in maize, sorghum and rice; Chilo suppressalis, Chilo polychrysus and Chilo supermain are major pests of rice; Chilo auricilius causes damage on both rice and sugar-cane; and Chilo infuscatellus and Chilo sacchariphagus indicus are serious pests of sugar-cane. Chilo suppressalis simplex and Chilo tumidicostalis are minor pests of maize and sugar-cane, respectively. Some of these pyralid borers are minor pests of other cereal crops. The life and seasonal histories of these stem borers and various control measures against them practised in various countries of southern Asia are discussed. The natural enemies of various Chilo species in this region are also listed.

Status and control of Chilo spp. on cereal crops in southern Asia

The studies on "Estimation of losses and management of maize stem borer, Chilo partellus (Swinhoe) in Kharif maize" were conducted during 2013, 2014 and 2015 in the Punjab. The key insect pest of Kharif maize was found to be C. partellus, however the insect pests other than C. partellus were of minor importance. The deadhearts incidence of C. partellus was significantly lower in the crop sown on 25 th June (6.07, 7.06; and 7.29, 9.11 %) than that in the crop sown during last week of May (9.17, 10.24; and 10.30, 11.99 %) and on 10 th of June (8.09, 9.06 & 9.08, 11.06 %) at Ludhiana and Jalandhar during 2013 and 2014, respectively. Accordingly, the maize grain yield was significantly higher in the crop sown on 25 June (54.51, 54.58; and 52.85, 52.02 q/ ha) than that in the crop sown during last week of May (52.69, 51.34; and 49.91, 48.70 q/ ha) and on 10 th of June (52.53, 51.01; and 50.88, 50.01 q/ ha) at Ludhiana and Jalandhar during 2013 and 2014, respectively. The mean maize grain yield losses caused by C. partellus ranging from 10.99 to 14.69 per cent, were also lower in the crop sown on 25 June than that sown during last week of May and on 10 June. The laboratory evaluation of different isolates of Beauveria bassiana Balsamo (Vuillemin) against C. partellus revealed that the Local isolate (caused 39.00 % mortality of C. partellus) followed by Bb 4668 (caused 31.75 % mortality of C. partellus) isolate of B. bassiana were most virulent against C. partellus. However, Mycojaal, Bb 7126, Bb 7130 and Bb 4644 isolates of B. bassiana were moderately (caused 19.7522.50 % mortality of C. partellus); and Bb 5412, Bb 5408 isolates of B. bassiana were least virulent (caused 17.50-18.00 % mortality of C. partellus) against C. partellus. The evaluation of Local, Bb 4668 and Mycojaal isolates of B. bassiana against C. partellus under artificial infestation conditions in screen house revealed that the Local isolate was most effective against C. partellus. The field evaluation of different Integrated Pest Management (IPM) strategies against C. partellus revealed that the standard check treatment i.e. deltamethrin was most effective (with deadhearts incidence of 6.256.85 %) against C. partellus. The treatments i.e. Bacillus thuringiensis var. kurstaki, chlorantraniliprole @ 8, 10 and 12 Kg/ ha and maize intercropped with one or two rows of cowpea (with deadhearts incidence of 9.80-11.96 %) being at par with each other were moderately effective against C. partellus. The cowpea fodder yield obtained in maize intercropped with cowpea treatments provided additional benefit. The seed treatment with imidacloprid; water based and talc based formulation of Local isolate of B. bassiana (with deadhearts incidence of 14.11-16.46 %) being at par with each other were least effective against C. partellus. The present studies clearly showed that the effective management of C. partellus involves integration of different management strategies.

Estimation of losses and management of maize stem borer, Chilo partellus (Swinhoe) in Kharif maize

Twenty-seven species of Chilo which infest graminaceous crops are listed. The effects of various cultural practices such as time of planting, plant density, field sanitation, tillage, mulching, intercropping, proper fertilizer and water management on field populations of Chilo spp. are discussed. These practices have great potential as components of IPM for resource-limited farmers in the tropics.

Cultural Control of Chilo spp. in Graminaceous Crops

Pest and disease incidence in pearl millet under different plant density and intercropping patterns

Pest Management and the Environment

Growing sorghum in association with cowpea or lablab reduced sorghum stem borer infestation. On sorghum as a pure crop, 32.6% stem borer damage was recorded, while intercropped with lablab or cowpea it was 9.2 and 16.4% respectively. Sorghum raised with lablab or cowpea yielded 4652 and 4567 kg of grain per ha respectively while pure sorghum yielded 3509 kg. When the phytochemicals extracted from the legumes lablab or cowpea were sprayed on sorghum they prevented oviposition by gravid females of C. partellus for up to six days.

S. Chelliah

Papers

Influence of intercropping legumes with sorghum on the infestation of the stem borer, Chilo partellus (Swinhoe) in Tamil Nadu, India