RAGWORT CONTROL

Waikato Independent, Volume XL, Issue 3664, 6 February 1940, Page 2

RAGWORT CONTROL

BREEDING OF SEED FLY SATISFACTORY INVESTIGATIONS ° jf'issi The result of investigations carried out by Mr David Miller, Assistant Director and Chief Entomologist at the Cawthron Institute, in connection, with the liberation of a seed fly to check ragwort, are contained in a letter he has sent to Mr W. J. Broadfoot, M.P., as follows: "I made an inspection of Mr Riggir's farm near Putaruru on January 15th, and was very pleased with what I saw in regard to the progress of the insect, though it is much too early yet to make any definite statement; but I feel that if the insect increases during the next few seasons at the same rate it has recently done, then there should be some clear evidence of the ability of the insect to reduce the seeding of the weed. "I also visited another area of the abandoned mill site at Selwyn, where I have also liberated the insect, and there I found without any difficulty infested flowers. It would thus seem that the insect is gradually breeding up a population. I am continuing the work of establishing the insect, and for this purpose I have selected an isolated area of ragwort on a section of Crown land near Rotorua." Continuing, Mr Miller says it cannot be too strongly impressed upon farmers that even if this seed fly becomes effective in controlling the seeding of the ragwort it will be still necessary for farmers to maintain their fight against it by ordinary farm practice, as the insect will be effective only in reducing . the weed on areas, in-, • a|^j^^^;||^' but % wnicW"are source of infestation to farm lands.

The entomologist also makes the following reference to the bidibidi parasite: "Progress with this insect is very slow, and it will be some time before any definite signs of its efficiency under field conditions can be seen. I am still liberating the insect on ; the experimental areas where I wish to concentrate all the supplies I have in the meantime in order to build up a sufficient population to demonstrate the possibilities of the parasite before I commence general liberations."