0 & 2 - 
& S I E E 'A L FEEDERS 
GRASSHOPPERS (Acrididae) 
Arizona. B. M. Gaddis and assistants (April 21-26): Hatching of Me lanoplus 
mexicanus Sauss., the only grasshopper of major importance in crop 
areas of Maricopa and Yuma Counties, is practically complete. In- 
festations in the Roll-WeLlton district of Yuma County are general and 
severe in some fields; however, in other sections of the county only 
scattered localized infestations exist. Very few fields in Maricopa 
County have threatening-to-severe infestations. (April 27-May 3) ; 
Fifteen percent of M. mexican us have reached the adult stage, while 
in Maricopa County the range in nymphal development is from first to 
fifth instar. Grasshopper damage in the afore-mentioned counties is 
■becoming more evident; in several fields of the Roll-Wellton district, 
damage to alfalfa ranged from 5 J °° 100 percent. (May 4-10 ): Maricopa 
County grasshopper infestations are somewhat lighter than was ejected 
hut are much lighter than in 1940. A few first and second instars of 
M. difforentialis Thos. have been observed during the past week. The 
range grasshopper ( Trimorotropis pallidipennls Burn. ) has moved into 
the vicinity of crops in this county but no demage has resulted, 
(May 11-17): Warm and dry weather in t'he southern portion of the 
State was favorable to rapid development of . grasshopper eggs and 
nymphs during the week. M. mexicanus now comprises approximately 75 
percent of the species present and M. differential! s from 15 to 20 per- 
cent. Most M. mexicanus are in tlie adult stage, while M. differenti- 
al is ranges from first to third instar. 
Colorado^ (May 4-10 ): The hatch of M. mexicanus and Aooloplus turnbullii 
Thos. was 50 percent complete in southeastern Colorado. Populations 
ranged from 5 to 50 per square yard in fields and from 10 to 150 per 
square yard on margins. (May 11-17): Weather conditions throughout 
eastern Colorado were highly favorable for egg and nymphal develop- 
ment. The dominant species in the irrigated areas are M. bivittatus 
Say, M, difforentialis , M. mexicanus , and A, turnbullii , in the order 
named. In the dry-land farming areas, the species in order of import- 
ance at present are A. turnbullii , M. bivittatus , M. mexicanus , and 
M. packardii Scudd. The hatch is 65 percent complete in southeastern 
Colorado and 15 percent complete in the northeastern section of the 
State. M, bivittatus and M, difforentialis comprise 60 percent of the 
grasshoppers in the irrigated-f arming areas. Wynphs have not migrated 
into crops in large numbers, owing to the abundant vegetation avail- 
able along field margins. 
Hew Mexico, (April 21-26): Severo.l first-instar M. mexicanus and one 
second-instar M, bivittatus were observed in an alfalfa field. (May 
4-10): M. bivittatus was beginning to hatch in favorable habitats 
along the Rio Grande Valley. (May 11-17): Hatching of M. bivittatus 
V 
Where no name is given after the State the report is by B. M, Gaddis end 
assistants. 
