COOPERATIVE SPRAY PROGRAM BEGUN IN BORDER AREA 



When the first fly was discovered near Tijuana in January and the in- 

 tensified survey revealed the presence of light infestation, spray programs 

 were started on both sides of the border. 



On the Mexican side representatives of the U.S. Department's Plant Pest 

 Control Branch cooperated with Mexican officials in setting up and carrying 

 out a spray program on all known host fruit trees within an area reaching as 

 far below the border as Ensenada. Susceptible fruit trees are sprayed with 

 a tartar emetic solution every third week. 



A similar spray program in cooperation with the California Department 

 of Agriculture has been under way in lower San Diego and Imperial Counties 

 since May. There are few commercial plantings of citrus on either side of 

 the border in the Tijuana-San Ysidro area, but backyard "patio" plantings 

 abound. On the California side some 20, 000 trees are sprayed regularly on 

 3, 000 properties. 



The triweekly spray program in the Mexicali-Calexico area, which was 

 halted in July, was resumed in October. This break in the spray schedule 

 was possible because there are few if any known host fruits available to the 

 pest during the late summer. 



LONG-TIME COOPERATION WITH MEXICO 



The U. S. Department of Agriculture has been cooperating with the Mex- 

 ican Secretaria de Agricultura on the fruit fly problem since shortly after 

 the insect was found in Texas in 1927. 



As communication and travel developed in Mexico, the fruit fly made its 

 way to the West Coast of Mexico. At first it was found only as far north as 

 Culiacan, Sinaloa, but it has since moved or has been carried steadily north- 

 ward. The present threat in California stems from this movement. In 1953 

 the fly was found in Hermosillo, Sonora, only a little more than 100 miles 

 below the Arizona border. This area recently has been linked by highway and 

 rail transportation with the extreme northwest part of Baja California, for- 

 merly cut off by desert. Shipment of subtropical fruits, particularly man- 

 goes, became a part of the commerce developing over these new routes. 



Foreseeing a possible invasion route for the fly, the U.S. Department 

 assisted Mexico in establishing and maintaining a highway control point at 

 San Luis, Sonora, where mangoes, or any other host fruits, could be given 

 an ethylene dibromide fumigation. In addition, Mexican authorities now in- 

 spect train baggage of passengers traveling north at Enpalme, Sonora; fumi- 

 gate railway and baggage cars carrying fruit at Benjamin Hill, Sonora; and 

 inspect all baggage and cargo arriving off northbound planes at Ensenada, 

 Mexicali, and Tijuana. 



