BLIGHT ON BLUE GUM TREES.

Otago Witness, Volume 23, Issue 2684, 23 August 1905, Page 54

BLIGHT ON BLUE GUM TREES.

WELLINGTON, August 16. In reference to the blight that has attacked the trees in the blue gum plantations in Canterbury, the biologist of the Department of Agricultrre reports as follows: — "I have carefully examined the blue gum plantations of the South Island. Th© damage is being done by an imported scale insect, which is killing the trees. Owing to the height of many of the trees it is impossible to spray them; but there is_ a small ladybird beetle, a native of Australia, known as Rhizobius ventralis, which does * great deal to keep the scale in check. Last year I wrote and made arrangements _ to receive successive supplies of this ladybird, and have received several letters from the experts in Australia regretting that owing to the extremely unfavourable season they had not been able to collect. In a letter received on the 6th ult. it was stated that the ladybirds would not be available till the end of the present month. Even then, if the weather is severe, I may have to hold them in the laboratory, as to liberate them) in the south during bad weather would be fatal. „ I am, however, promised & succession of consignments, and this should meet the case. A letter just to hand states that it is hoped to fpUeot -tjhe insects very soon. Should the natural enemy fail, then the only way to prevent the spread of the scale would be to cut down the infested! plantations, let the trees break again from the stumps, and 'spray thoroughly. This would kill out the scale. There is no powe* at present to compel any action. The Orchard and Garden Pests Acfcj. tinder thei title of the Vegetation Diseases Act, gave power to deal with such outbreaks as this and potato diseases. Parliament, however, limited its operations to er&bixdg 0#& jrardens.'*