In Mexico, the spittlebug, Aeneolamia albofasciata (Homoptera, Cercopidae), is the most economically detrimental insect herbivore of buffelgrass Cenchrus ciliaris. Buffelgrass (native to Africa) was introduced to Sonora in 1954 to increase productivity in semi-arid regions of northern Mexico. Although the focus of this study (undertaken on the Carbo Livestock Research Station, Sonora) was to use summer burning to reduce spittlebug populations in buffelgrass, results may serve to identify best prescribed burning management practice to retain spittlebugs in areas where buffelgrass itself is considered a pest.
The five treatments were applied to buffelgrass pasture:
1) an unburned control;
2) burning 7-14 days before summer rains when spittlebug and buffelgrass inactive;
3) burning after the accumulation of 5 cm of summer rainfall during spittlebug egg hatch or buffelgrass second leaf stage;
4) burning between the second and third instars or early grass culm elongation;
5) burning between the fifth instar and adult stages or peak buffelgrass growth during the summer.
Effect of treatments on different lifestages of spittlebug and and growth and motality of buffelgrass were recorded over 4 years.
Summer burning after accumulation of 5 cm of rainfall and between egg hatch and the third instars or between the second leaf stage and early culm elongation totally eliminated spittlebug nymphs and adults. Additionally, buffelgrass growth appeared stimulated for 3-4 years post-burn. Burning at the peak of buffelgrass growth, whilst also effectively controlling spittlebugs reduced grass production by almost 50% for 4 years post-burn. In the untreated control, nymph and adult spittlebugs killed more than 50% of the buffelgrass.
An advantage of summer burning conducted after the first rains was that fires were easier to control than those undertaken before the growing season when vegetation was dry.