Impact of the SpittlebugMahanarva spectabilison Signal Grass

Abstract

The aim of this study was to determine the damage in Brachiaria ruziziensis (Germain & Edvard) according to the density of and exposure time to adults of Mahanarva spectabilis (Distant, 1909) (Hemiptera:Cercopidae). Each plant was kept with 0, 12, 18, or 24 adults of M. spectabilis for five or ten days. Then, the insects were removed from the plant, and the following parameters were evaluated: content and loss of chlorophyll, visual damage score, shoot dry mass, and the capability for regrowth. In fact, plants exposed to the highest level of infestation for 10 days showed an 80.97% loss of chlorophyll, which is 25% higher than that shown by the plants exposed for five days. The damage score also increased with infestation levels. In the levels of 12 and 18 adults per plant, the damage score increased with increasing time of exposure. The dry mass content was higher in plants exposed to 24 insects for 10 days, suggesting that the attack of spittlebugs caused premature drying of the plant. These effects caused significant reduction in the number of tillers of infested plants. Our results indicate that exposure to adults of M. spectabilis causes significant damage and affects the development and persistence of B. ruziziensis plants.

Resistance mechanisms of sugarcane cultivars to spittlebug Mahanarva fimbriolata

“…These authors agree that susceptible plant cultivars tend to show greater reductions in chlorophyll levels than tolerant cultivars do when attacked by pests (Flinn et al, 2001;Boina et al, 2005;Diaz-Montano et al, 2007;López et al, 2009). For example, Resende et al (2012) recorded a reduction of up to 81 % in chlorophyll levels in Brachiaria ruziziensis due to attack by M. spectabilis adults. According to these authors, toxic saliva injected into the leaves by adults interferes with photosynthetic activity.…”

Tolerance to nymphs and adults of Mahanarva spectabilis (Hemiptera: Cercopidae) by forage plants in fertilized soils

“…Frequent attacks may also decrease the volume of the root system and the forage's persistence . Injuries caused by spittlebug feeding also result in the early drying of plants, a decrease in fresh weight and consequently, an increase in the percentage of dry matter . In the case of RUZ 2, there was no percentage increase for any bioassay, which differed from the results of Resende et al .…”

Do silicon and nitric oxide induce resistance to Mahanarva spectabilis (Hemiptera: Cercopidae) in forage grasses?

“…after attack by M. spectabilis adults also occurs after damage caused by spittlebug feeding. According to Resende et al , the feeding of M. spectabilis causes early senescence in plants, which reduces their fresh weight and, consequently, leads to a dry matter percentage increase.…”

“…Spittlebug species of the genus Mahanarva are crucial pests in Brazilian pastures, particularly the species Mahanarva spectabilis (Distant, 1909) (Hemiptera: Cercopidae) . As sucking insects, spittlebugs cause damage by sucking the xylem sap and injecting salivary secretions into the vegetative tissue, leading to leaf death .…”