432 XXIII. LEGUMINOSAE 



(v) Insects. The two most destructive insect pests of the babul are the 

 beetles Coelosterna scahrata, Fabr., and PsilojJtera jastuosa, Fabr., an account 

 of which by E. P. Stebbing is contained in Forest Bulletin No. 12 of 1912. 

 The former, which is the more dangerous of the two, is a root-boring longicom, 

 the grubs of which tunnel in the roots and kill young trees : the imago strips 

 the bark from the leading shoots and branches of yomig trees. The latter 

 beetle is a buprestid, which as far as is kno^\'n attacks trees only in its mature 

 stage, stripping the bark off the shoots and branches. 



(vi) Fungi. Much damage is caused in Berar by the fungus Fom,es Pap- 

 pianus, Bres. This fungus attacks the heartwood of the stem and branches 

 and spreads into the roots, causing the wood to become brittle, and in severe 

 cases to crumble away : infected trees are thus liable to be blo^\Ti over or to 

 have their stems and branches snapped in two by wind. The fungus does not 

 attack young healthy trees, but only those w^hich are in an unhealthy condition 

 or have ceased to grow vigorously owing to injury or to old age : it attacks 

 isolated trees as well as those growing in dense crops. It has not yet been 

 ascertained whether the fungus spreads imderground tlirough the roots by 

 means of mycelia or through wounds above ground by means of spores, or 

 both. 



Measures which have proved efficacious in keeping the fungus in check 

 are: (1) to remove all sporophores from infected trees ; (2) to cut out badly 

 infected trees ; (3) to execute regular thinnings in young crops, removing sickly 

 stems and promoting vigorous growth in those retained ; (4) to cultivate the 

 soil with field crops after the babul crop has been removed, and to keep the 

 young babul crop healthy by hoeing the groimd and promoting soil-aeration. 



(vii) Lopping. Lopping for fodder and thorn hedges is a source of much 

 injury to the babul : in some cases the lopping takes the particularly destructive 

 form of half cutting through the branches and bending them down to be within 

 the reach of goats and cattle, a jagged wound being thus formed : small trees 

 are similarly cut half through a few feet from ground-level and broken down. 

 Although the babul has great capacity for heahng womids, jagged wounds 

 formed by rough methods of lopping do not heal, and become centres of 

 infection by rot. It is by no means improbable that lopping may prove to 

 be one of the chief causes of the spread of fungus attacks. 



Natural reproduction. Under natural conditions germination com- 

 mences early in the rainy season and continues for some time. Much moisture 

 and warmth are necessary to effect complete germination, and without these 

 the seed may lie dormant for two seasons or more and then germinate if con- 

 ditions are favourable. Experiments at Dehra Dun in which seed was sown 

 under varying degrees of shade and temperature showed that germination 

 was considerably retarded under even slight shade, owing to the reduction of 

 temperature, and that when it did take place the seedlings were unable to 

 persist for any length of time in the absence of complete light. 



The dangers to which the seedling is exposed during and after germina- 

 tion have been mentioned above under ' the seedling ', and these are all factors 

 inimical to natural reproduction. 



It may be said generally that the conditions essential for the stimulation 

 of vigorous natural reproduction are: (1) complete sunlight, (2) abundant 



