Army Mystery Worm. 391 



ARMY MYSTERY WORM. 



Action in Case of Recurrence. 



The suiiiiuer of 1918-1919 will long be remembered for the extra- 

 ordinary outbreaks of the Mystery Army Worm (Laphyc/vui exempta) 

 ill various parts of the Union, and the consequent loss of grazing and 

 tefl:'-grass which would have been invaluable during the terrible 

 drought through which the area affected has since passed. During 

 the following summer little was heard of the insect. Early in March, 

 1919, a plant inspector of the Division of Entomology found larvse 

 rather numerous in a few localities in and near Durban. They were 

 most abundant in swampy places at TJmgeni, but three acres of young 

 sugar-cane in a nearby plantation had been completely fed off by 

 them, numerous parasites of a number of kinds were busy amongst 

 them, and wilt disease was also observed. The presence of the insect 

 elsewhere in the country was not confirmed, although in December, 

 1919, two official reports of outbreaks were made to the Division. 

 The first of these came from Gqobonco, Engcobo district, Transkei, 

 and the other from the Beaufort West district, where the caterpillar 

 was observed in considerable numbers on certain farms shortly after 

 the first rains fell. 



Beyond these two early reports nothing further was heard, but 

 the pest must have been present and breeding in the south-westerc 

 districts, for on the 26th April, 1920, Mr. David Gunn, the 

 Entomologist stationed at Port Elizabeth, reports : "I received an 

 urgent request for assistance from farmers near Witteklip, on the 

 Avontuur railway line (TJitenhage district). One farmer stated that 

 millions of caterpillars were present in his fields, and were destroying 

 all his crops. I proceeded to AVitteklip on the morning of the 21st 

 instant, and met a number of farmers who infonned me that extensive 

 damage had been done to potato, barley, and maize fields. In several 

 instances large fields of barley had been completely destroyed, and 

 would have to be resowm. Upon visiting the farm Rocklands, I found 

 that about ten acres of barley had been completely destroyed, and 

 half of a large field of young maize plants which was grown as gi'een 

 fodder for dairy cows. About three-quarters of a field of potatoes had 

 also been completely destroyed. Million.<i of caterpillars were present 

 on this farm, and at the request of farmers in the neighbourhood I 

 prepared a quantity of sweetened poisoned bait in order to save a field 

 of young maize. As millions of caterpillars in all stages of develop- 

 ment were feeding on the plants, two boys with large branches of 

 trees were first sent through the field in the afternoon to brush the 

 caterpillars on to the ground, and afterw^ards the sweetened poisoned 

 bait was sown thinly throughout the rows. The field was examined 

 the following morning, and the work was found to be successful, as 

 every caterpillar which had been brushed off the plants had eaten the 

 bait and had died in consequence. The farmers were fully satisfied 

 with this demonstration., and proceeded to thei farms to adopt the 



