(Hemiptera: Cercopidae) Should Be Used for Screening Brachiaria Ruziziensis (Poales: Poaceae) Resistance?

PLANT RESISTANCE How Many Adults of Mahanarva spectabilis (Hemiptera: Cercopidae) Should be Used for Screening Brachiaria ruziziensis (Poales: Poaceae) Resistance?

1 T. T. RESENDE, A. M. AUAD, AND M. G. FONSECA Embrapa Dairy Cattle Research Center, CEP 36038-330, Juiz de Fora, MG. Brazil Downloaded from https://academic.oup.com/jee/article/107/1/396/832188 by guest on 25 September 2021

J. Econ. Entomol. 107(1): 396Ð402 (2014); DOI: http://dx.doi.org/10.1603/EC13297 ABSTRACT This study determined the number of spittlebug adults, Mahanarva spectabilis Distant (Hemiptera: Cercopidae), that should be used in selection tests of the forage grass, Brachiaria ruziziensis (Germain and Evrard). In this study, 0, 1, 2, 4, or 8 M. spectabilis adults were kept in plants for 4 or 8 d per experimental plot. After these periods, the insects were removed from the plants and chlorophyll content, damage score, dry weight, fresh weight, and percent dry matter of shoots were evaluated. Chlorophyll content decreased signiÞcantly with higher density of M. spectabilis in plants exposed to the pest for 4 or 8 d. Plants that were exposed to eight spittlebugs for 8 d showed a Ϸ60% loss of chlorophyll content. When the forage was infested with eight adults for 4 d, the average damage score was 3 (50% of the leaf area was affected). The damage score and fresh and dry weights of the forage did not change depending on the exposure time of the plants to the spittlebugs. The percentage of dry matter of the plants infested was higher with the increase insect density and exposure time for all densities. Thus, the minimum recommended number is eight M. spectabilis adults for4din resistance tests of B. ruziziensis to this pest species.

KEY WORDS forage, signal grass, spittlebug

The Brachiaria are widely used as forage in tropical stopped, which causes necrotic lesions that spread America (Miles et al. 2004). The use of these grasses longitudinally toward the leaf apex (Holmann and as forage is widespread because of its adaptation to Peck 2002). Consequently, the aggregate impact of acidic soils with low fertility, resistance to intensive nymphs and adults reduces regrowth in these forages grazing and trampling of animals, and its good forage and contributes to the degradation of pastures yield (Keller-Grein et al. 1996). The species Brachiaria (Vale´rio and Nakano 1987), which causes economic ruziziensis (Germain and Evrard) has a high nutri- losses from US$840 to US$2,100 million per year world- tional value (Lascano and Euclides 1996); however, wide (Thompson 2004). this forage is susceptible to spittlebugs (Keller-Grein As the chemical control of spittlebugs is not eco- et al. 1996), which may compromise its quality and nomically and ecologically feasible, the use of this production (Souza Sobrinho et al. 2010). control method is limited in pastures (Macedo 2005). Spittlebugs are common from southern United Therefore, selection of forage that is resistant to spit- States to northern Argentina. Each locality has its tlebug nymphs is common because it is efÞcient, can own speciÞc complex of spittlebugsÑdiffering ac- comprise many plants, and is relatively inexpensive cording to genus, the most important being the genera (Cardona et al. 1999). Hence, most research is focused Deois, Notozulia, Aeneolamia, Prosapia, and Mah- on the selection of spittlebug nymphs by antibiosis anarva (Vale´rio et al. 2001)Ñthat damage pastures (Vale´rio et al. 1997, Auad et al. 2007, Cardona et al. and affect the forage supply of animals (Paula-Moraes 2010, Souza Sobrinho et al. 2010), and there are few 2006, Auad et al. 2007). Insects of the genus Mahanarva studies on resistance to the adults because of the may kill the forage depending on the time of year and difÞculty of working with this life stage. their population density (Auad et al. 2007). However, according to Lo´pez et al. (2009), even Spittlebug nymphs and adults feed mainly on the forage resistant to spittlebug nymphs appears to be xylem of host plants (Thompson 2004); however, adult susceptible to the adults of these insects. In addition, spittlebug attack is more severe because they cause Cardona et al. (2004) indicate that it is necessary to phytotoxicity in susceptible hosts and inject toxins select forage with antibiosis that are capable of causing during feeding (Byers and Wells 1966, Vale´rio et al. signiÞcant mortality to the spittlebug nymphs and has 1988). Thus, the photosynthetic activity of the plant is some tolerance to the damage caused by adult spittlebugs. According to Miles et al. (2006), numerous 1 Corresponding author, e-mail: [email protected]. interspeciÞc hybrids of Brachiaria with high levels of

0022-0493/14/0396Ð0402$04.00/0 ᭧ 2014 Entomological Society of America February 2014 RESENDE ET AL.: SCREENING B. ruziziensis RESISTANCE TO SPITTLEBUG 397 antibiosis to nymphs of important species of spittlebug made for air ßow and were installed on a pot contain- have been obtained. Lo´pez et al. (2009) developed ing B. ruziziensis. The plots were maintained in trays methods for evaluating the resistance of forage to and placed in the greenhouse. The treatments with adults of Aeneolamia varia (F.) and Zulia carbonaria eight replicates consisted of releasing zero, one, two, (Lallemand). Cardona et al. (2010) found weak cor- four, or eight adults with the same ratio of males to relations with the damage generated by the nymphs females of M. spectabilis per experimental plot, except and adults, which conÞrmed that resistance to the in treatment with one adult. Any dead insects were different life stages is largely independent. replaced daily to maintain a constant density of M. The search for cultivars resistant to adult spittlebugs spectabilis for 4 or 8 d. After the insects were removed is important because adults cause more damage than from the plant, the plants were evaluated by the fol- nymphs, and the adults can migrate between pastures lowing parameters: chlorophyll content, damage (Fewkes 1969, Fontes et al. 1995, Peck 1999, Sujii et al. score, and the percentage of the shootsÕ dry matter.

2000). Lo´pez et al. (2009) suggest that adults from Chlorophyll content was measured by the 502 OL Downloaded from https://academic.oup.com/jee/article/107/1/396/832188 by guest on 25 September 2021 grasses susceptible to spittlebug nymphs can migrate SPAD Minolta device (Konica Minolta Sensing; to areas with plants that are resistant to nymphs. Thus, Osaka, Japan) before infestation (n ϭ 16), after4dof according to Cardona et al. (2004), the cultivars that infestation (n ϭ 8) and after8dofinfestation (n ϭ 8) are resistant to nymphs that lack tolerance to the adult in three leaf blades of a tiller from the plant, which spittlebugs will suffer the same damage as the cultivars measured the mean chlorophyll content of each plant. that are susceptible to spittlebug nymphs. Considering In addition, we calculated the percentage of chloro- the importance of developing techniques for the se- phyll loss from each treatment as follows: percentage lection of forage cultivars resistant to M. spectabilis of chlorophyll loss ϭ [(U Ϫ I)/U] ϫ 100, where U ϭ adults, this study determined the optimal number of SPAD reading for uninfested plants and I ϭ SPAD M. spectabilis adults that should be used in selection reading for infested plants for each density (Deol et al. tests of B. ruziziensis. 1997). The visual damage of the leaf area of each plant was evaluated as a percentage by three evaluators, and the Materials and Methods mean was converted to a damage score from 1 to 5 Plants and Insects. Seeds of commercial B. ruzizien- (Cardona et al. 1999). After analysis, the mean damage sis were deposited in trays (50 cm long, 30 cm width, in forage was classiÞed based on the mean score, 14 cm height) with commercial pine bark substrate which was adapted from Pabon et al. (2007). A score (Plantmax, Paulõ´nia, Sa˜o Paulo, Brazil), and the seed- between 1 and 2 indicates that the grass tolerated lings were transplanted to plastic tubes (35 cm3) Þlled insect attack, a score between 2.1 and 3 indicated with commercial pine bark substrate after 30 d. After intermediate tolerance, and a score Ͼ3 indicated that 60 d of transplanting, the seedlings were transplanted the plant was susceptible to insect attack. and grown in pots (12 cm in diameter, 10 cm in height) After exposure to the insects for 4 or 8 d, the plants with a liter of substrate (soil, manure, and sand in a subjected to different densities of insects were cut at ratio of 3:1:1) and kept in a greenhouse. Thirty days ground level, and the fresh weight of the leaves and before the start of the experiment, the shoots were cut stems were measured immediately after cutting. close to the soil level to standardize plant size, and the These materials were dried at 55ЊC for 72 h, and their soil was submitted to fertilization with 140 mg/dm3 of dry weights were recorded. Subsequently, the per- NPK 20-5-20, as recommended by soil analysis. On the centage of dry matter and the functional plant loss day the plants were infested, they had a mean height index (FPLI), which was proposed by Morgan et al. of 76.2 Ϯ 0.9 cm, 13.9 Ϯ 0.4 tillers, and an average (1980) and modiÞed by Panda and Heinrichs (1983), chlorophyll content of 40.6 Ϯ 0.5 SPAD units. were calculated. This index is calculated based on the The adult M. spectabilis specimens used in all the damage score (DS), dry weight of uninfested plants experiments were derived from a colony maintained (DWUP), and dry weight of infested plants (DWIP) in a greenhouse from Embrapa Dairy Cattle. The ex- as follows: FPLI (%) ϭ [1 Ϫ (DWIP/DWUP) ϫ (1 Ϫ periment was conducted in a greenhouse at a mean DS/5)] ϫ 100, and this method is considered a useful temperature of 25.3ЊC (minimum ϭ 17.7 and maxi- tool for quantifying tolerance (Smith et al. 1994). mum ϭ 39.7ЊC), 83.2% mean relative humidity (RH; Statistical Analysis. The average chlorophyll con- minimum ϭ 38.3 and maximum ϭ 99.5%), and 28 tent from three leaf blades of each plant, percentage lum/ft2 mean intensity light (minimum ϭ 1.0 and of chlorophyll loss, rate of functional loss, damage maximum ϭ 664.0 lum/ft2). These parameters were score, fresh weight, and dry weight of the shoots and recorded using a HOBO DATALOGGER (Onset Co., percentage of dry matter were compared by analysis Pocasset, MA) every 2 min and transferred to a soft- of variance (ANOVA). When the ANOVA was signif- ware (Hobowere), and these values represent the icant, regression analysis of the density of infestation means during the experimental period. or the means were compared by TukeyÕs test (P Յ Experiment. Randomized blocks with Þve densities 0.05) to evaluate the effect of exposure time of the of insects and two exposure times were used in the grass to the spittlebugs (4 and 8 d). experiments. Each plot consisted of a transparent cy- The analyses were performed using SISVAR (2010) lindrical plastic cage (70 cm high and 19 cm in diam- (Federal University of LavrasÐMinas Gerais, Brazil). eter), and in all extensions 3 mm-diameter holes were The Pearson correlation between the chlorophyll con- 398 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 107, no. 1 Downloaded from https://academic.oup.com/jee/article/107/1/396/832188 by guest on 25 September 2021

Fig. 1. Relationship between infestation levels of adult Fig. 3. Relationship between infestation levels of M. spec- M. spectabilis and chlorophyll content (SPAD unit) in B. tabilis adults and damage scores for B. ruziziensis over4or8d. ruziziensis over4or8d.

forage over 4 (r ϭϪ0.80; T ϭϪ8.38, P Ͻ 0.0001) or tent and damage score was calculated using BioEstat 8d(r ϭϪ0.73; T ϭϪ6.73, P Ͻ 0.0001) of exposure of 5.0 (Federal University of Para´ÐPara´, Brazil). the plants to the spittlebug. The rate of functional loss signiÞcantly increased Results with increasing infestation densities of spittlebug for 4d(F ϭ 3.001; df ϭ 3; P ϭ 0.045; Fig. 4). However, We observed no signiÞcant differences in the chlo- there was no signiÞcant difference between the in- rophyll content of plants before exposure to M. spec- festation densities when the plants were infested for tabilis adults (F ϭ 0.73; df ϭ 4; P ϭ 0.56), which 8d(F ϭ 1.001; df ϭ 3; P ϭ 0.404), and the functional conÞrmed the standardization of the plantÕs chloro- losses of the plants were 40.79, 38.84, 48.77, and 57.56% phyll content. In tests conducted after infestation, the when exposed to 1, 2, 4, and 8 adults, respectively. chlorophyll content decreased signiÞcantly depend- The increased density of M. spectabilis adults did not ing on the increased density of spittlebug infestation signiÞcantly alter the fresh weight (F ϭ 1.497; df ϭ 4; in plants exposed for 4 (F ϭ 21.80; df ϭ 4; P Ͻ 0.001) P ϭ 0.2210 and F ϭ 0.270; df ϭ 4; P ϭ 0.8952) and dry and8d(F ϭ 25.34; df ϭ 4; P Ͻ 0.001), and the quadratic weight (F ϭ 1.477; df ϭ 4; P ϭ 0.2271 and F ϭ 0.576; regression curves for both exposure times are pre- df ϭ 4; P ϭ 0.6812) of Brachiaria plants infested for 4 sented in Fig. 1. Therefore, there was an increased and 8 d, respectively. However, the infestation den- chlorophyll loss depending on the density of infesta- sities promoted a signiÞcant increase in the dry matter tion at 4 (F ϭ 11.90; df ϭ 3; P Ͻ 0.001) and8d(F ϭ percentage for 4 (F ϭ 5.093; df ϭ 4; P ϭ 0.0021) and 7.27; df ϭ 3; P Ͻ 0.001) of exposure of the plants to the 8d(F ϭ 3.556; df ϭ 4; P ϭ 0.0143) of infestation insects (Fig. 2). The higher the infestation density of M. (Fig. 5). spectabilis, the greater the damage score to the plants With regard to the duration of infestation, it was exposed to Cercopidae for 4 (F ϭ 31.13; df ϭ 4; P Ͻ observed that plants exposed to only one adult had 0.0001) or8d(F ϭ 34.53; df ϭ 4; P Ͻ 0.0001; Fig. 3). signiÞcantly less chlorophyll content after8dofin- Using correlation analysis, the damage scores are festation (F ϭ 10.08; df ϭ 2; P ϭ 0.001). There was a inversely related to the chlorophyll content of the signiÞcant difference among the exposure times with

Fig. 2. Relationship between infestation levels of adult Fig. 4. Relationship between infestation levels of M. spec- M. spectabilis and percentage of chlorophyll losses in B. tabilis adults and functional plant loss indexes (%) for B. ruziziensis over4or8d. ruziziensis after4dofexposure. February 2014 RESENDE ET AL.: SCREENING B. ruziziensis RESISTANCE TO SPITTLEBUG 399 Downloaded from https://academic.oup.com/jee/article/107/1/396/832188 by guest on 25 September 2021

Fig. 5. Relationship between infestation levels of M. spec- Fig. 7. Relationship between percentage of chlorophyll tabilis adults and dry mass percentage of B. ruziziensis. losses in B. ruziziensis and exposure time (4 and 8 d) at different infestation levels of M. spectabilis adults. Mean values followed by the same letter within the levels of in- two insects (F ϭ 36.36; df ϭ 2; P Ͻ 0.001). There was festation did not differ by TukeyÕs test. also a signiÞcant reduction in the chlorophyll content ϭ ϭ Ͻ of plants exposed to four (F 55.97; df 2; P 0.001) four adult spittlebugs for 8 d and tolerated the attack ϭ ϭ Ͻ and eight adults (F 86.32; df 2; P 0.001) at 4 and of one adult insect for8dortwoadults for 4 d. 8 d compared with the initial assessment. The exper- Between exposure times, there was no difference in imental time did not promote a natural reduction in the rate of functional loss when the plants were ex- the chlorophyll content among the three evaluations posed to one (F ϭ 0.002; df ϭ 1; P ϭ 0.9692), two (F ϭ ϭ ϭ ϭ (F 1.269; df 2; P 0.280) in the noninfested plants 0.179; df ϭ 1; P ϭ 0.6757), four (F ϭ 0.088; df ϭ 1; P ϭ (Fig. 6). Moreover, differences were observed in the 0.7689), or eight (F ϭ 0.033; df ϭ 1; P ϭ 0.8571) adult chlorophyll loss between time points only when the insects. When the plants were exposed to the insects ϭ plants were exposed to two spittlebug adults (F for 4 d, only one adult of M. spectabilis per plant was ϭ ϭ 10.01; df 1; P 0.002), and the losses for the relative sufÞcient to generate a functional loss of Ϸ40% in B. density of infestation after8dofexposure were 2.5- ruziziensis, whereas a 57% loss was observed with eight fold higher than those at 4 d (Fig. 7). adults. The longer exposure time (8 d) resulted in a There was no increased damage score with increas- signiÞcant increase in the percentage of dry matter ϭ ing time when the plants were exposed to one (F compared with4dofinfestation (Fig. 8), whereas this ϭ ϭ ϭ ϭ ϭ 0.00; df 1; P 1.000), two (F 0.46; df 1; P 0.49), parameter was similar in both exposure times in un- ϭ ϭ ϭ ϭ four (F 0.00; df 1; P 1.00), or eight (F 0.46; infested plants. df ϭ 1; P ϭ 0.49) M. spectabilis adults. From the damage score caused to the forage at 4 d of infestation, B. ruziziensis was susceptible to the attack of eight Discussion adults of M. spectabilis. However, B. ruziziensis dis- The reduction in the chlorophyll content of plants played intermediate tolerance to attack by two and exposed to M. spectabilis adults resulted in a yellow streaking of the leaves of the grasses with increased

Fig. 6. Relationship between chlorophyll content (SPAD unit) of B. ruziziensis and exposure time (0, 4, and 8 d) Fig. 8. Dry mass percentage of B. ruziziensis infested at different infestation levels of adult M. spectabilis. Mean during 4 or 8 d with adults of M. spectabilis. Mean values values followed by the same letter within the levels of in- followed by the same letter within the levels of infestation did festation did not differ by TukeyÕs test. not differ by TukeyÕs test. 400 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 107, no. 1 infestation densities and exposure to M. spectabilis. d with Þve adults of A. varia or Z. carbonaria is the According to Ajayi and Oboite (1999), these symp- minimal time for resistance tests. Therefore, the ex- toms can be confused with nutrient deÞciency, espe- posure time of the plant to insect pests as well as the cially nitrogen, which can lead to erroneous decision number of insects used in the resistance tests depends making regarding their control. on the spittlebug species that are being studied be- Resende et al. (2012) found a signiÞcant reduction cause there is considerable variation in aggressiveness in the chlorophyll content of B. ruziziensis with an among the species. This variation was reported by increased density and exposure to M. spectabilis that Vale´rio (1995), who observed more extensive damage ranged from 0 to 24 adults over 5Ð10 d. in B. decumbens compared with Notozulia entreriana Chlorophyll declined with increasing time of expo- by M. fimbriolata. Vale´rio (2006) also reported the sure only in the plants exposed to two M. spectabilis death of plants after infestation with spittlebugs of adults. At higher densities, B. ruziziensis had the ability the genus Mahanarva in the B. brizantha cultivar to compensate for the loss of chlorophyll; it is likely ÔMarandu.Õ Although this is resistant to spittlebug Downloaded from https://academic.oup.com/jee/article/107/1/396/832188 by guest on 25 September 2021 that there were changes in the plantÕs metabolism, nymphs by antibiosis, it showed slight recovery in case which resulted in an increased photosynthetic rate to of more severe attacks. prevent the continued reduction in the chlorophyll Cardona et al. (2010) found a damage score of 3.3 content. A similar observation was veriÞed by Auad et for B. decumbens infested with Þve adults of Aeneola- al. (2010) when evaluating the effect of the attack of mia reducta (Lallemand) for 7 d. These results are D. schach and M. spectabilis nymphs on elephant grass. similar to the current study, which denoted that the When plants were exposed to a lower density and larger the population of M. spectabilis, the greater the shorter exposure time, only one adult for 4 d, the loss loss from the attack of adults; however, the attack of of chlorophyll was Ͼ10%, whereas those exposed to one adult was sufÞcient to damage the forage grown the highest density and longest exposure time, eight in pots. adults for 8 d, had a chlorophyll loss of Ϸ60% (Fig. 7). Currently, resistance testing of forage is focused on Lo´pez et al. (2009) observed that the attack of only selecting plants resistant to nymphs, which will not one A. varia adult for up to 10 d resulted in Ϸ20% loss always act for the two stages of insect life, corroborates of chlorophyll in Brachiaria genotypes that are sus- the results of Cardona et al. (2010) who found that ceptible to spittlebug nymphs. Their results are similar Brachiaria hybrids are resistant to spittlebug nymphs to those in this study because plants infested with one but not the adults. Thus, it is likely that there is an M. spectabilis adult for 8 d showed Ϸ20% loss of chlo- independent mechanism in the resistance to spittle- rophyll. The signiÞcant loss of chlorophyll in B. ruzi- bug nymphs compared with adults (Sotelo et al. 2008, ziensis infested with adults of M. spectabilis may affect Cardona et al. 2010), which makes it necessary to the photosynthetic capacity of the plant because in- select forage that is resistant to both life stages of sects cause changes in water transport, stomata open- Cercopidae. It is highlighted that because of the dif- ing, and sucrose transport when feeding (Nabity et al. Þculty of handling large numbers of adults and the fact 2009), which reduces photosynthesis in the remaining that adult damage score can be misleading, Cardona et leaf tissue of the attacked plants. al. (1999) suggested screening of tolerant plants in- Four days of infestation were sufÞcient to show fested with spittlebug adults, when these plants signs of damage, which corroborates the results of showed resistant to nymphs by antibiosis mechanism. Vale´rio and Nakano (1992), who found the Þrst chlo- Resende et al. (2012) and Lo´pez et al. (2009) found rotic spots in Brachiaria decumbens on the third day a high correlation between the damage score and after infestation with Zulia entreriana. However, the chlorophyll content of Brachiaria infested with adult damage was signiÞcantly equal for both exposure spittlebugs. This may be a useful parameter when times regardless of the density used in this study. performing resistance tests in Brachiaria as the geno- During periods of exposure of B. ruziziensis, the dam- types capable of maintaining the chlorophyll content ages may be considered early (that makes it difÞcult after attack by adult spittlebugs will be less damaged to detect signiÞcant differences), whereas according by insects. Moreover, SPAD is a useful tool for quan- to Vale´rio and Nakano (1992), the full and Þnal ex- tifying the chlorophyll content and should become an pression of the damage of spittlebugs in pastures oc- important indicator for selecting forage-resistant curs 23 d after infestation. adults of M. spectabilis, which should reduce the sub- In this study, there was a damage score of 3 for B. jectivity of the analysis performed on material selec- ruziziensis attacked by eight adults of M. spectabilis for tion when visually ranking the damage. 4 d, which conÞrmed the results of Resende et al. Calculation of the functional plant loss index mea- (2012). However, a damage score of 3.5 in B. ruzi- sures plant tolerance to insects (Morgan et al. 1980 ziensis attacked during5dby12adults of M. spectabilis modiÞed by Panda and Heinrichs 1983). According to shows a trend of increasing damage with an increasing Lo´pez et al. (2009), the functional plant loss index is density of insects. Cardona et al. (1999) also found that the best index for estimating tolerance of Brachiaria to the Brachiaria cultivar is susceptible to attack by A. spittlebugs. The values observed in the current study varia, and its damage increased with increasing num- conÞrm the low tolerance of B. ruziziensis to attack of bers of adults per plant; these authors suggest that six M. spectabilis adults because one insect per plant for adults of A. varia must be kept for 10 d to perform 4 d reduces Ϸ40% of plant functionality. Moreover, the resistance tests. Lo´pez et al. (2009) suggest that 7Ð10 rate of functional loss increased signiÞcantly with in- February 2014 RESENDE ET AL.: SCREENING B. ruziziensis RESISTANCE TO SPITTLEBUG 401 creasing infestation densities for plants infested for bicincta (Homoptera: Cercopidae). Ann. Entomol. Soc. 4 d. Resende et al. (2012) observed that 12 adults of M. Am. 59: 1067Ð1071. spectabilis attacking for 5 d was sufÞcient to generate Cardona, C., J. W. Miles, and G. Sotelo. 1999. An improved a functional loss of Ͼ75% in B. ruziziensis, which dem- methodology for massive screening of Brachiaria spp. onstrates that increased infestation densities result in genotypes for resistance to Aeneolamia varia (Ho- a signiÞcant increase in functional loss. moptera: Cercopidae). J. Econ. Entomol. 92: 490Ð496. Cardona, C., P. Fory, G. Sotelo, A. Paboń, G. Diaz, and J. W. Lo´pez et al. (2009) found a functional loss index Miles. 2004. Antibiosis and tolerance to Þve species of between 60 and 80% when B. ruziziensis was infested spittlebug (Homoptera: Cercopidae) in Brachiaria spp.: with two and seven adults of A. varia, respectively, for implications for breeding for resistance. J. Econ. Entomol. up to 10 d. Cardona et al. (2010) found a functional loss 97: 635Ð645. index of 81.7 and 81.9% in B. decumbens subjected to Cardona, C., J. W. Miles, E. Zuniga, and G. Sotelo. 2010. attack by Þve adults of A. varia and A. reducta for up Independence of resistance in Brachiaria spp. to nymphs to 10 d of exposure. or to adult spittlebugs (Hemiptera: Cercopidae): impli- Downloaded from https://academic.oup.com/jee/article/107/1/396/832188 by guest on 25 September 2021 The longest exposure resulted in a signiÞcant in- cations for breeding for resistance. J. Econ. Entomol. 103: crease in the percentage of dry matter compared with 1860Ð1865. shorter times of infestation, and a similar observation Deol, G. S., J. C. Reese, and B. S. Gill. 1997. A rapid, non- destructive technique for assessing chlorophyll loss from was made in alfalfa infested with Philaenus spumarius greenbug (Homoptera: Aphididae) feeding damage on (Weaver and Hibbs 1952), clover infested with Pro- sorghum leaves. J. Kans. Entomol. Soc. 70: 305Ð312. sapia bicinta (Say) (Marthus and Pienkowski 1967), Fewkes, D. W. 1969. The biology of sugar cane froghoppers, and B. decumbens infested with N. entreriana (Vale´rio pp. 283Ð307. In J. R. Williams, R. W. Metcalfe, R. W. and Nakano 1988). The increase in the percentage of Mungomery, and R. Mathes (eds.), Pests of Sugar Cane. dry matter can be associated with the reduced fresh Elsevier, Amsterdam, The Netherlands. weight of plants because of the damage caused by Fontes, E. G., C. S. Pires, and E. R. Sujii. 1995. Mixed risk insect feeding. Moreover, according to Vale´rio and spreading strategies and the population dynamics of a Nakano (1988), spittlebug attack reduces grass palat- Brazilian pasture pest, Deois flavopicta (Homoptera: Cer- ability, which signiÞcantly reduced animal acceptance copidae). J. Econ. Entomol. 88: 1256Ð1262. Holmann, F., and D. C. Peck. 2002. Economic damage of the forage. caused by spittlebugs (Homoptera: Cercopidae) in Co- The method of using forage that is resistance to lombia: a Þrst approximation of impact on animal pro- spittlebugs is currently the most viable control strat- duction in Brachiaria decumbens pastures. Neotrop. En- egy; however, the number of M. spectabilis adults that tomol. 31: 275Ð284. should be used in resistance tests is unknown. Based Keller-Grein, G., B. L. Maass, and J. Hanson. 1996. Natural on this study, the use of eight adults of M. spectabilis variation in Brachiaria and existing germplasm collec- for4disrecommended in resistance tests of B. ruzi- tions, pp. 16Ð42. In J. W. Miles et al. (eds.) Brachiaria: ziensis to this pest species. Biology, Agronomy, and Improvement. CIAT, Cali, Co- lombia, and CNPGC/EMBRAPA, Campo Grande, MS, Brazil. Lascano, C. E., and V.P.B. Euclides. 1996. Nutritional qual- Acknowledgments ity and animal production of Brachiaria pastures, pp. We thank the Conselho Nacional de Desenvolvimento 106Ð123. In J. W. Miles et al. (eds.) Brachiaria: Biology, Cientõ´Þco e Tecnolo´gico (CNPq, Brazil) and Fundaçaõde Agronomy, and Improvement. CIAT, Cali, Colombia, and Amparo a` Pesquisa do Estado de Minas Gerais (FAPEMIG, CNPGC/EMBRAPA, Campo Grande, MS, Brazil. Brazil) for supporting our research. Lo´pez, F., C. Cardona, J. W. Miles, G. Sotelo, and J. Montoya. 2009. Screening for resistance to adult spittlebugs (Hemiptera: Cercopidae) in Brachiaria spp.: methods and categories of resistance. J. Econ. Entomol. 102: 1309Ð References Cited 1316. Ajayi, O., and F. A. Oboite. 1999. Importance of spittlebugs, Macedo, D. 2005. Seleçaõ e caracterizaçaõdeMetarhizium Locris rubens (Erichson) and Poophilus costalis (Walker) anisopliae visando o controle de Mahanarva fimbriolata on sorghum in West and Central Africa, with emphasis on (Hemiptera: Cercopidae) em cana-de-açu´ car. Ph.D. dis- Nigeria. Ann. Appl. Biol. 136: 9Ð14. sertation, Escola Superior de Agricultura Luiz de Quei- Auad, A. M., A. D. Simo˜es, A. V. Pereira, A.L.F. Braga, F. roz, Universidade de Saõ Paulo, Piracicaba. Souza Sobrinho, F.J.S. Le´do, S. V. Paula–Moraes, S. A. Marthus, R. B., and R. L. Pienkowski. 1967. Inßuence of Oliveira, and R. B. Ferreira. 2007. Seleçaõ de geno´tipos adult meadow spittlebug feeding on forage quality. J. de capim-elefante quanto a` resisteˆncia a` cigarrinha-das- Econ. Entomol. 60: 207Ð209. pastagens. Pesquisa Agropecua´ria Brasileira 42: 1077Ð Miles, J. W., C. B. Valle, I. M. Rao, and V.P.B. Euclides. 2004. 1081. Brachiaria grasses, pp. 745Ð783. In L. E. Moser, B. L. Auad, A. M., T. T. Resende, P. H. Monteiro, D. R. Santos, and Burson, and L. E. Sollenberger (eds.), Warm Season (C4) I.S.C.P. Maddalena. 2010. Avaliaçaõ da toleraˆncia de Grasses. ASA, CSSA, SSSA, Madison, WI. capim elefante a ninfas de Deois schach (Fabricius, 1787) Miles, J. W., C. Cardona, and G. Sotelo. 2006. Recurrent e Mahanarva spectabilis (Distant, 1909) (Hemiptera: Cer- selection in a synthetic Brachiaria grass population im- copidae), pp. 1Ð3. In Proceedings of the 23th Semana de proves resistance to three spittlebug species. Crop. Sci. Biologia da Universidade de Federal de Juiz de Fora, 2010, 46: 1088Ð1093. Juiz de Fora, UFJF, Juiz de Fora, MG. Morgan, J., G. Wilde, and D. Johnson. 1980. Greenbug re- Byers, R. A., and H. D. Wells. 1966. Phytotoxemia of coastal sistance in commercial sorghum hybrids in the seedling bermuda grass caused by the two spitllebug, Prosapia stage. J. Econ. Entomol. 73: 510Ð514. 402 JOURNAL OF ECONOMIC ENTOMOLOGY Vol. 107, no. 1

Nabity, P. D., J. A. Zavala, and E. H. Delucia. 2009. Indirect Cercopidae) as major pests of neotropical sugarcane and suppression of photosynthesis on individual leaves by forage grasses. Bull. Entomol. Res. 94: 189Ð200. arthropod herbivory. Ann. Bot. 103: 655Ð663. Vale´rio, J. R. 1995. About the evaluation of forage grasses Pabon, A., C. Cardona, J. W. Miles, and G. Sotelo. 2007. aiming resistance to the spittlebugs (Homoptera: Cer- Response of resistant and susceptible Brachiaria spp. ge- copidae), pp. 1058. In Proceedings of the 13th Interna- notypes to simultaneous infestation with multiple species tional Plant Protection Congress, Holanda. of spittlebugs (Hemiptera: Cercopidae). J. Econ. Ento- Vale´rio, J. R. 2006. Considerac¸o˜es sobre a morte de passta- mol. 100: 1896Ð1903. gens de Brachiaria brizantha cv. ÔMaranduÕ em alguns Panda, N., and E. A. Heinrichs. 1983. Levels of tolerance Estados do centro e norte do Brasil: Enfoque ento- and antibiosis in rice varieties having moderate resistance molo´gico. Embrapa Gado de Corte, Campo Grande, Bra- to the brown planthopper Nilaparvata lugens (Stål) sil. (Hemiptera: Delphacidae). Environ. Entomol. 12: 1204Ð Vale´rio, J. R., and O. Nakano. 1987. Dano causado por adultos 1214. da cigarrinha Zulia entreriana (Berg, 1879) (Homoptera:

Paula-Moraes, S. V. 2006. Cadeia produtiva da carne e´ amea- Cercopidae) na produçaõderaõ´zes de Brachiaria decum- Downloaded from https://academic.oup.com/jee/article/107/1/396/832188 by guest on 25 September 2021 çada por praga. (http://www.cpac.embrapa.br/materias_ bens Stapf. Anais da Sociedade Entomologica do Brasil 16: pripag/nucleotematico.html). 205Ð212. Peck, D. C. 1999. Seasonal ßuctuations and phenology of Vale´rio, J. R., and O. Nakano. 1988. Danos causados pelo Prosapia spittlebugs (Homoptera: Cercopidae) in upland adulto da cigarrinha Zulia entreriana na produçaõ e quali- pastures of Costa Rica. Environ. Entomol. 28: 372Ð386. dade de Brachiaria decumbens. Pesquisa Agropecua´ria Brasileira 23: 447Ð453. Resende, T. T., A. M. Auad, M. G. Fonseca, T. H. Santos, and Valerio, J. R., and O. Nakano. 1992. Sintomatologia dos T. M. Vieira. 2012. Impact of the spittlebug Mahanarva ´ danos causados pelo adulto da cigarrinha Zulia entreriana spectabilis on signal grass. Sci. World J. 2012: 1Ð6. (Berg, 1879) (Homoptera: Cercopidae) em Brachiaria SISVAR. 2010. Sistemas de analises de variancia para dados ´ ˆ decumbens Stapf. Anais da Sociedade Entomologica do balanceados: programa de analises estatõsticas e planeja- ´ ´ Brasil 21: 95Ð100. mento de experimentos. Versao 5.3 (Biud 75). Universi- ˜ Vale´rio, J. R., F. M. Wiendel, and O. Nakano. 1988. Injeçaõ dade Federal de Lavras, Lavras, MG. de secreço˜es salivares pelo adulto da cigarrinha Zulia Smith, C. M., Z. R. Khan, and E.M.D. Pathak. 1994. Tech- entreriana (Berg, 1879) (Homoptera: Cercopidae) em niques for evaluating insect resistance in crop plants. Brachiaria decumbens Stapf. Revista Brasileira de Ento- CRC, Boca Raton, FL. mologia 32: 487Ð491. Sotelo, P. A., M. F. Miller, C. Cardona, J. W. Miles, G. Sotelo, Vale´rio, J. R., H. Jeller, and J. Peixer. 1997. Seleçaõdein- and J. Montoya. 2008. Sublethal effects of antibiosis re- troduço˜es do geˆnero Brachiaria (Griseb) resistentes a` sistance on the reproductive biology of two spittlebug cigarrinha Zulia entreriana (Berg) (Homoptera: Cercopi- (Hemiptera: Cercopidae) species affecting Brachiaria dae). Anais da Sociedade Entomologica do Brasil 26: spp. J. Econ. Entomol. 101: 564Ð568. 383Ð387. Souza Sobrinho, F., A. M. Auad, and F.J.S. Le´do. 2010. Ge- Vale´rio, J. R., C. Cardona, D. C. Peck, and G. Sotelo. 2001. netic variability in Brachiaria ruziziensis for resistance to Spittlebugs: bioecology, host plant resistance and ad- spittlebugs. Crop. Breed. Appl. Biotechnol. 10: 83Ð88. vances in IPM, pp. 217Ð221. In Proceedings of the 19th Sujii, E. R., M. A. Garcia, and E.M.G. Fontes. 2000. Movi- International Grassland Congress, Saõ Pedro, Brazil. mentos de migraçaõ e dispersaõ de adultos da cigarrinha- Weaver, C. R., and J. W. Hibbs. 1952. Effects of spittlebug das-pastagens. Pesquisa Agropecua´ria Brasileira 35: 471Ð infestation on nutrition value of alfalfa and red clover. J. 480. Econ. Entomol. 45: 626Ð628. Thompson, V. 2004. Associative nitrogen Þxation, C4 photosynthesis, and the evolution of spittlebugs (Hemiptera: Received 25 June 2013; accepted 17 September 2013.