Arizona republican., 1910-01-07
\ CITRUS PEST
 OF FIRST RANK
A Horticultural Commission Circura
 on the Mealy Bug.

"Mealy Bugs Affecting Citrus" is the cultural commission. by A. w Morrill, entomologist of the commission The circular follows:
 Wherever mealy bugs have become well established in citrus groves they usually Outclass all competitors for first rank as citrus pests. Their seri- ousness is not entirely due to their di- rect injury but to the difficulty in sue cessfully controlling them This will be discussed in its proper place. In Arizona we are interested in them on account of few live specimens being found on citrus nursery stock shipped from Florida to Arizona last spring: also on account of live specimens be ing found near Phoenix in September 1909. on trees planted in March.
 There are two species of mealey bug which are citrus pests. one known a the citrus mealy bug and the other a the long spined nealy bug. The hab- its and appearance of the two ar much alike. The adult female insect is nearly one-fourth inch in length and mealy white in color. While the in sects often occur singly. they are usually found in masses on the fruit and in the angles of the twigs. The eggs are laid in white cottony secre- ton each mature female insect being reported to lay from $50 to 400. The insects infest stems. leaves and fruit of all kinds of citrus. but are 'lost de- structive to grapefruit in Florida and to lemons and navel oranges in Cali fornia
 The principal injury from mealy bug attack is in the sooty mould fungus which develops on the honey dew ex- creted by the insect This fungus is the same as that which follows the at tack of white fly and black scale Leaves and fruit become coated with a dense covering of this fungus and entire crops of fruit are sometimes rendered practically worthless. For reasons not understood. the citrus mealy bug in Florida sometimes be- comes a serious pest in one grove, more serious than white fly. while in neighboring groves it is of little. inn portance. In California it Is most abundant and destructive in San Diego and Ventura counties. but occasionally it is met with in nearly all sections of the southern part of the state.
 Mealy bugs are noted for their re sistance to sprays and to Immigration Their waxy coverings and secretions tend to prevent sprays from penetrat- ing to effect them and they are able to withstand hydrocyanic acid gas at strengths two and three times as great as that required to kill most other scale insects: Experience to date seems to show that satisfactory con trol by either method is impracticable In California reliance for control is at present centered on natural enemies. A lady bug imported from Australia is the most effective enemy so far known. There are several species Of internal parasites known to occur in California and Florida. but these do not seem to be of any practical im- portance. A parasite imported from China is being tested as to its ca pacity of assisting in the control of the pest. but so far no important results have been obtained.
 As stated in circular No. , of this series. the entomologist has thus far found only two live specimens of the citrus mealy bug in his inspections of citrus trees in the Salt river valley In th.s connection it should be noted that Professor T. D. A. Cockerell found at Tempe. Arizona, in 1899 a honeysuckle badly infested with a mealy bug which he states (Bul. g Arizona Az ricultural Experiment station) he could not distinguish from the citrus mealy bug.
 From the evidence at hand the cit rus mealy bugs would seem to thrive best in humid regions In general. however, the citrus mealy bug is not nearly so injurious in Florida as in some sections of California which are much less humid. Humidity is not the only factor which governs the adapta- bility of the insectionS to different points. It would be impossible to pre- dict the consequences if the colony of tablished during an unusually favor able season in region with climate such as that of the Salt river valley Even if the climatic conditions here should restrict them so that their numbers would not increase beyond by the writer in large orange and lemon grove in Santa Paula, California. their injury would be sufficient to greatly reduce the profits in citrus growing A w. MORRILL,,