IG4: Journal of the Department of Agriculture. 



Ill llic lilisll\('lil. (Illlill<; IMMlods (it (llnii^lii. llic li\iii,u piivts (if 

 wild luishes and shrubs are attacl^'d. sdiiict iincs tlic wIkiIc ul a sjuall 

 iiiiib beiii^' eaten away. This is explainable lirst because sueli busJics 

 are eonti^udus to nests and, secondly, on the ground that the insects 

 cannot otherwise, and readily, obtain the moisture essential to the 

 well-being- of their coninuinities. Tn this i)robably also lies the 

 explanation of their attack year aftei' yeai' on fruit trees growing 

 under similar sub-aiid conditions. 



It may also be mentioned tliat white ants do not in the usual run 

 of events attack green maize plants. Even when their nests are in the 

 lands they do not toucJi the growing plant, although wlien dead and 

 (li\ it forms a favourite food. Yet in tlie bushvcdd it is no unusual 

 tiling for green maize (o be eaten, and by the very same kinds whudi 

 elsewhere do not touch it. This behaviour imvy on]\- be set 

 down to a dearth of the ntuch-desii'ed moisture. 



Experience goe;? to sliow that fruit trees under irrigation, if Jiol. 

 oiigirially exempt from attack, become so. The reason for this seems 

 to lie in the i^epeated watering of the soil setting up a state of affairs 

 unsuited to ihe economy of the principal culprits, the Fungus 

 Growers. These require a certain amount of soil moisture for the 

 development and maintenance of their gardens, but, when that 

 moisture is continually in excess, the fungi they cultivate grow out 

 of their control and thereby virtually eliminate the colony. An 

 occasional watering or even flooding does not have this effect. There 

 is, however, some evidence to show that excessively wet summers have 

 led to the destruction of many colonies, especially in spots where there 

 has been a considerable rise in the water table. 



When wliite ants are troublesome in lands regulaidy under irriga- 

 tion, their nests vrill be found located in the drier lieadlands or in 

 the banks of water furrows. 



TIT. — Attack urox Citrus and Pi'.ac ii Tini-Ks. 



Leaving out (d' consideration a peculiar while ant wliicli. on 

 occasion, isolates its nest in the dead stiilis and limbs of citiais trees 

 on Ihe Natal co;isl, any attack upon eitius and peach trees is due to 

 one or another of tlie Fungus Growers, and is not to be regarded as a 

 regular matter in the Union, but rather as sonndhing quite unusual. 



Tjven whcii grov.ing under serious disadvantages, the peach, 

 lemon, orange, naarije, avocado, and mango are left alone by \\hile 

 ants. I have never received even a suggestion that the two last- 

 mentioned trees are atta(d<ed, and yet I have a case in mind where 

 all here listed were (uiten when set out in land fj'om which the thick 

 scrub, that characterizes the sea-board of Natal, was quickly removed 

 a)id at once planted to such trees. In this case there were so many 

 nests present in the soil, owing to the previous superabundance of 

 food, that the insects had to attack something or die. 



So immune is the peach accepted as being, even where Fungus 

 Growers are (}uite numerous, that this tiee is generally recognized as 

 thi^ stock to graft i)lums and apricots upon, so that they luay escape 

 attack. -However, I have seen peach trees severely, injured. The 

 worst case was one that should never have taken place, although the 

 nests of the marauding insects were quite contiguous to the trees. 

 These trees, and there was quite an orchard of then], had long been 



