1 Fup, 1900.] QUEENSLAND AGRICULTURAL JOURNAL. 135 
Entomology. 
CATERPILLAR PLAGUE. 
(Leucania unipuncta, Haw.) 
By HENRY TRYON, 
Entomologist. 
(Prares OLX XIL-IV.) 
A INTRODUCTORY. 
T two pawods of the year—September-October and March-May—reference . 
crops ound in the Press to serious ravages committed on pasturage and cereal 
Y caterpillars. ‘These caterpillars are the young of two night-flying 
rs Rap eown, perecayely> as Leucania unipuncta, Haw. (extranea, Gn.) and 
coneeen at mauritia, Boisd. Of these, the former is the insect that is generally 
Wed, and is the one to which subsequent remarks will be confined. _ 
Sanaa insect is one whose range of occurrence is very extended, being met 
i rego ne to EH. Meyrick, not only in Australia and New Zealand, but also 
Dears + be, Southern Asia, and North America. In the last-mentioned region it 
he Significant name of “army worm.” 
ita % ogee a chrysalis, or a moth, it is to be observed in districts that 
enemig 8 eu the year in varying degrees of prevalence. It has many 
insects Se ; ot only do birds devour it, but it is the prey also of many carnivorous 
eee 1s, however, most effectually held in check by internal parasites and. 
conditio oth fungus and bacterial; and, moreover, special meteorological 
Acton os determine the death of its eggs. Under ordinary circumstances these 
tndey Ber D ye. competent to hold it entirely in subjection; and it is only when, 
sus sala that are not fully understood, their operation is temporarily 
in ri ae , that a caterpillar plague manifests itself. "The occurrence of the insect 
Wen able numbers is also the occasion for its enemies to assert their fullest 
seasons 1 Hence it usually happens that a district is rarely visited in successive 
Hsiceh eae this pest, and, indeed, years may sometimes elapse between one 
lon und another. 
’ NATURE OF INJURY. 
ee caterpillars consume the foliage and stems of various species of native 
-°S, also those of introduced kinds--such as Panicum and Prairie (Bromus 
Yih 
rey Brown for hay or other purposes. ‘lhey alyo devour oats, rye, 
re ie. eat, maize, sorghum, and possibly young sugar-cane ; and will sustain 
those is fq by nibbling, and so damaging, the shoots of lucerne, and even 
@ ik the potato. Jn the ease of wheat not only is the flag consumed but 
iia Pht clets of the head may be eaten right back to the rachis, as is represented 
and fet CLXXIT. Rye in ear they will simply strip of every leaf, the bare stalks 
ay bes wlone remaining. Should the cereal not have already flowered, it 
diag © eaten down to the ground: a remark that especially applies to youn 
devoted” vestige of which may remain after caterpillars have passed over a fiel 
~ the eat to this crop. When young wheat has already been cut and tied up, 
And hilar may even eat the top of the shooks back for several inches. 
Visitation exceptionally the growth is sufficiently advanced at the time of their 
1b ne 3 for the crop, after cutting, to be dried for hay without risk of heating, 
Maras) © found that it has already become so soiled by the dead bodies of the 
ithe, «#8 to be wholly rejected by the animals to which it is presented, 
'n the form of chaff or otherwise. ‘Their destructive action, moreover, 1s 
NY thorough but it is also extensive. In the district of Ma Ma Creek, 
