. Insetti e Malattie delle piante : contenente rimedi e suggerimenti consigliati per l'adozione da parte degli agricoltori, frutta-dei coltivatori e giardinieri della provincia . Parassiti; le malattie fungine di piante; pesti di insetto. 60 Vict. Boaed provinciale di Orticoltura. 45 Il caso di Vedalia australiano cardinalis, unported a preda su scala scanalati Icerya purchctsi, è spesso citato come un esempio di ciò che può essere fatto. Quando questo insetto nemico è stato introdotto, è trovato nulla che sia riconosciuto ad eccezione del Icerya purcJiasi, e in seguito si dedicò interamente a tale specie, sopprimendo totalmente in un

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. Insect pests and plant diseases : containing remedies and suggestions recommended for adoption by farmers, fruit-growers, and gardeners of the province . Pests; Fungal diseases of plants; Insect pests. 60 Vict. Provincial Boaed of Horticulture. 45 The case of the Australian Vedalia cardinalis, unported to prey upon the fluted scale Icerya purchctsi, is frequently cited as an example of what can be done. When this insect enemy was introduced, it found nothing that it recognized except the Icerya purcJiasi, and in consequence devoted itself entirely to that species, totally suppressing it in a short time. All that was done here was to restore the "balance of nature." Nothing can be argued from this case as to the possibility of introducing foreign species to control strictly American pests with which they are not acquainted. We can, however, frequently do good where we have imported insects, or insects occurring also in other countries, by finding and introducing their parasites or enemies. In the Report of the California State Board of Horticulture for 1895-6, Mr. Alex. Oraw, Chief Quarantine Officer, says, referring to the work of beneficial insects in that State:—"I P ^ would go more fully into this subject to sustain your advocacy of this method benefit* °^ combating destructive scale insects, but time is rapidly proving that your policy has been wise and correct. We do not look for, nor have you ever stated that we can secure, complete extermination of our orchard pests by parasites; but who in California now fears the heretofore destructive 'cottony cushion scale, ' the 'pernicious scale, ' the 'yellow scale, ' the 'cottony grape scale, ' the 'soft orange scale, ' the mealy bugs, and we can soon add all the Lecaniums to the list." All the foregoing have been destructive in their time, and have been regarded with dread by orchardists. Of course, with the disappearance of their food, the parasites naturally disappear and the scale may show up a

Parole chiave associate all'immagine

• bookcentury1800
• bookdecade1890
• booksubjectinsectpests
• bookyear