Soil silicon amendments increase resistance of sugarcane to stalk borer Eldana saccharina Walker (Lepidoptera: Pyralidae) under field conditions

Background and aims

Soil amendment with silicon (Si) can significantly increase resistance of susceptible sugarcane cultivars grown in pots to stalk borer Eldana saccharina (Lepidoptera: Pyralidae). This study tested the hypothesis that a single application of silicate can increase resistance to E. saccharina and increase yield in field-grown sugarcane.

Methods

Two Si materials (Calmasil® and Slagment® at 4 and 8 t/ha) were applied at planting to a field trial extending over three successive crops and incorporating three sugarcane cultivars varying in borer susceptibility.

Results

Both materials, especially Slagment, significantly increased soil, leaf and stalk Si content, but leaf Si levels seldom exceeded 0.5 %. Silicon treatment significantly reduced percent stalks bored in all three crops and stalk length bored in the second ratoon crop, but did not affect borer numbers per 100 stalks (E/100) or increase cane or sucrose yield. Borer damage and E/100 were significantly and consistently reduced in the resistant cultivar.

Conclusions

We argue that if leaf Si% in field sugarcane can be elevated to or exceed 0.8 %, using materials that release Si slowly, substantial reductions in stalk damage and sucrose loss could be achieved in susceptible cultivars in low-Si soils.     

Relative effects of parents on some economic characters in sugarcane

Studies on the relative effects of parents on some economic characters in sugarcane have given indications of maternal influence in the progeny performance in certain crosses with regard to millable canes at harvest, height of stalks and brix per cent in juice, irrespective of the fact that pollen parent effect was positive or negative. As judged from a study of the progeny of the direct crosses and reciprocals among the varieties studied, particularly use of Co. 678 as a pistil parent in the breeding programme for improving the mean height of the progeny and Co. 527 as a pistil parent for increasing number of millable canes at harvest and brix per cent in juice is clearly indicated. These indications should also prove useful for application in adopting the polycross method of breeding as well. Approved for presentation by the Director, Sugarcane Breeding Institute, Coimbatore.     

Response of eight sugarcane cultivars to glyphosine and glyphosate ripeners

Studies were conducted on eight sugarcane (Saccharum spp. hydrid) cultivars during the 1982–83 (plant crop) and 1983–84 (ratoon crop) growing seasons to determine the effects of glyphosine (Polaris) (N,N-bis (phosphonomethyl) glycine) and glyphosate (Polado) (sodium-N-(phosphonomethyl) glycine) on stalk sucrose content and yield. Difference due to crops (plant vs. ratoon) for sugarcane quality, kilograms of sugar per ton of cane (S/T), sugarcane yield, tons of cane per hectare (TCH), and sugar yield, tons of sugar per hectare (TSH) were significant. Significant differences were found in quality for the ratoon crop and cane and sugar yield in both crops due to ripener treatment. Cultivars in both crops differed significantly in quality and yield. Harvest dates were significantly different for all plant characteristics. Interactions of cultivar by treatment for the plant crop, harvest date by treatment for the ratoon crop, and cultivar by harvest date for both crops for cane quality also were significant. Time from ripener application to achievement of maximum sugar concentration also depended on cultivar. This is important in determining the economic benefits of a ripener treatment. Climatic conditions may also affect the benefits of such applications.Mention of trade name or proprietary product does not imply or constitute an endorsement or recommendation by the USDA or the University of Florida.     

九个甘蔗新品种在桂林地区的适应性观察和评价

为探讨甘蔗新品种在桂林地区的适应性表现,该研究以ROC22为对照,采用大区互比法,对国家甘蔗产业技术体系的9个甘蔗品种进行1年新植2年宿根的区域试验,观察记录出苗率、分蘖率、株高、产量和糖分等14个性状表现,并利用DTOPSIS法进行综合评价。结果表明:桂糖29号、桂糖31号、云蔗03-194、粤糖60号、福农38号和粤糖55号的综合性状表现优于对照ROC22,其中桂糖29号宿根性好、蔗茎产量和产糖量较高,但病虫害有不同程度的发生,田间栽培需加强病虫害防控;桂糖31号有效茎多、蔗糖分高,建议加强肥水管理,提高产量;云蔗03-194出苗率较高,出苗整齐,有效茎数较多,宿根性好,但枯心苗和黑穗病发病程度较其他品种严重,建议加强苗期病虫管理,保障成茎率;粤糖60号蔗糖产量较高、抗倒伏能力强,但新植出苗率较低,建议加大下种量;福农38号蔗糖分较高、抗病性较好,是优异的抗病材料;粤糖55号宿根性较好。上述筛选出的6个甘蔗品种宿根性好、抗逆性强、高产高糖,适宜在桂林地区进行扩大种植,用于指导当地的甘蔗示范推广。     

Response of eight sugarcane cultivars to glyphosine and glyphosate ripeners

Studies were conducted on eight sugarcane (Saccharum spp. hydrid) cultivars during the 1982–83 (plant crop) and 1983–84 (ratoon crop) growing seasons to determine the effects of glyphosine (Polaris) (N,N-bis (phosphonomethyl) glycine) and glyphosate (Polado) (sodium-N-(phosphonomethyl) glycine) on stalk sucrose content and yield. Difference due to crops (plant vs. ratoon) for sugarcane quality, kilograms of sugar per ton of cane (S/T), sugarcane yield, tons of cane per hectare (TCH), and sugar yield, tons of sugar per hectare (TSH) were significant. Significant differences were found in quality for the ratoon crop and cane and sugar yield in both crops due to ripener treatment. Cultivars in both crops differed significantly in quality and yield. Harvest dates were significantly different for all plant characteristics. Interactions of cultivar by treatment for the plant crop, harvest date by treatment for the ratoon crop, and cultivar by harvest date for both crops for cane quality also were significant. Time from ripener application to achievement of maximum sugar concentration also depended on cultivar. This is important in determining the economic benefits of a ripener treatment. Climatic conditions may also affect the benefits of such applications.     

Silicon-mediated resistance of sugarcane to Eldana saccharina Walker (Lepidoptera: Pyralidae): effects of silicon source and cultivar

Abstract:  The effects of four silicon sources – a USA calcium silicate, a local (South African) calcium silicate, Slagment^® and fly ash – on the resistance of sugarcane cultivars (two resistant and two susceptible) to Eldana saccharina Walker (Lepidoptera: Pyralidae) were studied in a potted sugarcane trial. Silicon sources were applied at 5000 or 10 000 kg/ha for the calcium silicates and Slagment; fly ash was applied at 15 000 or 30 000 kg/ha. The greatest increase in plant silicon content (particularly in stalks) was recorded for plants treated with local calcium silicate. Silicon uptake did not vary significantly between the susceptible and resistant cultivars, although the resistant cultivars had inherently higher silicon content than the susceptible ones. Treatment with silicon significantly reduced borer damage and borer performance at the higher treatment level. In general, borer damage and performance decreased with increasing rates of applied silicon and both variables were inversely related with per cent stalk silicon. On average, the higher silicon rate reduced damage by 34% in the susceptible cultivars and by 26% in the resistant cultivars, supporting the argument that susceptible cultivars benefit more from silicon treatments than resistant ones. We propose that calcium silicate amendments could be employed in the integrated, area-wide management of E. saccharina and in the management of soil acidity, both of which are widespread problems in the South African sugar industry.     

Morphological characteristics of sugarcane and insect resistance

Physiological, chemical and morphological make-up of the different sugarcane clones have a great impact on the resistance to various insect pests.Resistance to internode borer (Proceras indicus) has been found associated with the girth and the length of the top 1 to 5/6 immature internodes.A low number of stomata per unit has been associated with the resistance character of varieties to sugarcane scale (Melanaspis glomerata).Similar several morphological characters in sugarcane varieties have been found associated with resistance to moth borer (Diatraea saccharalis), whitefly (Aleurolobus barodensis), pyrilla (Pyrilla perpusilla), Mite (Oligonychus indicus), eriophyid mite and black bug (Macropes excavatus).

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Zusammenfassung Die physiologische, chemische und morphologische Ausstattung der verschiedenen Zuckerrohr-Klone hat eine große Bedeutung für die Resistenz gegenüber verschiedenen Insekten.Die Resistenz gegen den Internodienbohrer (Proceras indicus) ist nachweislich mit Umfang und Länge der oberen 5–6 Internodien verbunden.Eine geringe Spaltöffnungszahl steht in Beziehung zu den Resistenzeigenschaften der Sorten gegen die Zuckerrohr-Schildlaus (Melanaspis glomerata).Verschiedene ähnliche morphologische Eigenschaften der Zuckerrohr-Sorten erwiesen sich als verknüpft mit ihrer Resistenz gegen den Zuckerrohrbohrer (Diatraea saccharalis), die Mottenschildlaus (Aleurolobus barodensis), die Zikade Pyrilla perpusilla, die Spinnmilbe Oligonychus indicus, eine Gallmilbe und die Schwarze Wanze (Macropes excavatus).

     

Control of Diatraea saccharalis by the endophytic Pantoea agglomerans 33.1 expressing cry1Ac7

Despite the fact that Bacillus thuringiensis (Bt) is found in more than 90 % of the products used against insects, it has some difficulty reaching the internal regions where the larvae feed. To solve this problem, many genetically modified microorganisms that colonize the same pests have been developed. Thus, the endophytic bacterium Pantoea agglomerans (33.1), which has been recently described as a promising sugarcane growth promoter, was genetically modified with the pJTT vector (which carries the gene cry1Ac7) to control the sugarcane borer, Diatraea saccharalis. Firstly, the bioassays for D. saccharalis control by 33.1:pJTT were conducted with an artificial diet. A new in vivo methodology was also developed, which confirmed the partial control of larvae by 33.1:pJTT. The 33.1:pJTT strain was inoculated into sugarcane stalks containing the D. saccharalis larvae. In the sugarcane stalks, 33.1:pJTT was able to increase the mortality of D. saccharalis larvae, impair larval development and decrease larval weight. Sugarcane seedlings were inoculated with 33.1:pJTT, and re-isolation confirmed the capacity of 33.1:pJTT to continuously colonize the sugarcane. These results prove that P. agglomerans (33.1), a sugarcane growth promoter, can be improved by expressing the Cry protein, and the resulting strain is able to control the sugarcane borer.     

Binomial sequential sampling of adult Saccharicoccus sacchari on sugarcane

The between-stalk dispersion characteristics of adults of the pink sugarcane mealybug Saccharicoccus sacchari (Cockerell) were determined in southern Queensland. Iwao's patchiness regression was inappropriate to describe the relationship between mean and variance. Taylor's power law indicated that adults were aggregated, especially at the beginning and end of the ratoon growth period. Binomial data were modelled by the Nachman model; the model of Grout and two models of Wilson & Room were inappropriate to describe the relationship between proportion of stalks infested and mean numbers of adults per stalk. Relationships to determine sample sizes for fixed levels of precision and binomial fixed-precision-level stop lines are developed for different sampling times using Taylor's power law and Nachman's equation.     

Biology of suckers: late-formed shoots in sugarcane

Suckers in sugarcane are tillers that form late in the growing season after the population of main stalks has been established. Their biology has rarely been studied, though unsubstantiated comments relating to their morphology, development and number are abundant. In this paper, the literature is reviewed and new experiments presented. Comparison of suckers, emerging plant and ratoon cane showed that suckers have a different leaf and stem morphology. Suckers have a greater diameter at their stem base and shorter and wider leaves than primary stalks of a similar age. In 1 ‐year‐old crops, suckers have been demonstrated to decrease the net sucrose concentration of harvested material by diluting sucrose in the main stalks. By comparing main stalks without suckers to those that have initiated suckers, evidence is presented that suckers may also be decreasing the sucrose content of the stalks from which they are growing. Genotypic and environmental factors influence sucker number. Several experiments were designed to identify environmental stimuli for suckering. Increased nitrogen, through application late in the growing season, was found to increase the numbers of suckers present. Manipulation of the light environment of main stalks showed that a change in light quality (but not necessarily quantity) stimulated suckering. Further work is underway to define how these environmental stimuli lead to sucker initiation and growth. Major scientific questions that should be addressed are: the identification of other potential environmental stimuli, how the signals are perceived and translated into sucker initiation, and why suckers have different morphology. The practical challenge is to combine the new information about sucker biology and develop from it strategies to alter agronomy and select new cultivars that results in decreased suckering.     

Stem borer infestation of cereal crops in Jere,the Sudan-Sahelian savanna region of Nigeria

Field data collected during the rainy season of two years, 2010 and 2011, were used to determine the per cent plant infestation and stem borer abundance on cultivated cereal crops grown by farmers' in Jere or the Sudan-Sahelian savanna ecological region of Nigeria. Stem borers were recovered using destructive sampling. Mean total per cent plant infestation and stem borer abundance per farmers' field were significantly higher on millet (40% and 25 individuals, respectively) and sorghum (30% and 21 individuals, respectively) than on maize (19% and 13 individuals, respectively). Of the five stem borer species found in this study, Coniesta ignefusalis (Lepidoptera: Pyralidae) (3.5)/Chilo sp. nr. aleniellus (Lepidoptera: Crambidae) (2), Busseola fusca (Lepidoptera: Noctuidae) (3.1)/Sesamia calamistis (Lepidoptera: Noctuidae) (2.4) and S. calamistis (2.9), with significantly higher number of individuals per plant, tended to be more important pests on millet, sorghum and maize crops, respectively. Although, mean total per cent plant infestation and abundance of stem borers in this study were generally moderate, further studies on the effects of different types of cereals intercropping (locally practiced) on stem borer infestation and abundance should ascertain the true importance of these pest species in the Sudan-Sahelian savanna ecological region of Nigeria.     

低氮条件下甘蔗-大豆间作对甘蔗产量、品质及经济效益的影响

为探究甘蔗-大豆间作对甘蔗产量、品质及经济效益的影响,在施用尿素150 kg·hm^-2条件下,选择3个甘蔗品种(B8、ROC22及GT21)进行了甘蔗单作、甘蔗-大豆间作两种种植模式的试验.结果表明： 甘蔗-大豆间作对甘蔗的有效茎数、茎径以及原料蔗、蔗糖产量均有显著影响,而对原料蔗品质影响不大;与单作相比,间作大豆处理的宿根蔗茎径大小、有效茎数、蔗茎产量和糖产量分别提高5.1%～8.7%、7.9%～31.0%、9.0%～40.5%和5.6%～39.5%;每公顷原料蔗+大豆、糖+大豆可分别增收5.89～7.93万元和5.83～7.72万元;3个品种中,ROC22间作大豆的经济收益最高,而宿根蔗B8和GT21的产量均高于ROC22.表明甘蔗-大豆间作是减少氮肥施用、提高经济收入的有效栽培措施.     

Detection of sugarcane yellow leaf virus,the causal agent of yellow leaf syndrome in sugarcane by DAS-ELISA

DAS-ELISA studies were conducted on detection of sugarcane yellow leaf virus (SCYLV) causing yellow leaf syndrome (YLS) of sugarcane in leaf and juice antigens. Among the two types of antigen sources used for the virus detection, juice antigen showed high titre for the virus as compared to leaf antigen. Assay with juice samples recorded more number of varieties positive to the virus. Further DAS-ELISA studies revealed that plants raised from disease-infected planting materials recorded high titre for SCYLV as compared to those raised from symptom-free seed canes. Similarly, assaying SCYLV titre in plant and ratoon crop in the field showed that SCYLV infection was partial in plant crop and in the subsequent ratoon crop, all the samples were positive to the virus. ELISA studies also indicated that 33 of 41 cane varieties showing YLS were positive to the virus.     

Incidence and Severity of Leifsonia xyli subsp. xyli Infection of Sugarcane in Sao Paulo State,Brazil

Sugarcane covers 8.53 million hectares with production of 596.63 million tonnes in Brazil. Despite its importance, little information is available on ratoon stunt (RSD), caused by Leifsonia xyli subsp xyli (Lxx). Our objective was to examine the incidence and severity of Lxx among sugarcane cultivars in 2009, 2010 and 2011. Sap from 100 stalks from each field was sent for a routine RSD analyses that allowed examination of Lxx incidence. The presence of bacterium was checked by dot blot enzyme immunoassay to detect its presence and relative concentration. Analyses of 187 fields from 35 cultivars in 2009, 166 fields from 33 cultivars in 2010 and 221 fields from 30 cultivars in 2011 found Lxx incidence of 23.6% of fields of 23 cultivars in 2009, 27.1% of fields of 15 cultivars in 2010 and 25.8% of fields of 15 cultivars in 2011. RB867515, the major cultivar in Sao Paulo, had within‐field incidence of up to 70% in 2009, 48% in 2010 and 88% in 2011. Highest incidence and populations of Lxx infection were found for cvs RB867515, RB855453, SP81‐3250, RB855536 and RB92579, demonstrating their susceptibility to RSD.     

Engineering sugarcane cultivars with bovine pancreatic trypsin inhibitor (aprotinin) gene for protection against top borer (Scirpophaga excerptalis Walker)

The inhibitory activity of bovine pancreatic trypsin inhibitor (aprotinin), a natural polypeptide and a proteinase inhibitor, was demonstrated on gut proteinases of three lepidopteran borers of sugarcane using commercially available aprotinin. A synthetic gene coding for aprotinin, designed and codon optimized for better expression in plant system (Shantaram 1999), was transferred to two sugarcane cultivars namely CoC 92061 and Co 86032 through particle bombardment. Aprotinin gene expression was driven by maize ubiquitin promoter and the plant selection marker used was hygromycin resistance. The integration, expression and functionality of the transgene was confirmed by Southern, Western and insect bioassay, respectively. Southern analysis showed two to four integration sites of the transgene in the transformed plants. Independent transgenic events showed varied levels of transgene expression resulting in different levels (0.16–0.50%) of aprotinin. In in vivo bioassay studies, larvae of top borer Scirpophaga excerptalis Walker (Lepidoptera: Pyralidae) fed on transgenics showed significant reduction in larval weight which indicated impairment of their development. Results of this study show the possibility of deploying aprotinin gene for the development of transgenic sugarcane cultivars resistant to top borer.     

Nature and assessment of losses caused by sugarcane borers

On the two main types of sugarcane borers, viz. top and stalk borers, the latter are generally more harmful than the former. In the young crop stalk borers cause dead hearts, but at later stages their attack is normally restricted to the joints, except in (almost) mature cane when again many tops may be destroyed. In this paper emphasis is on assessing the extent of infestation and the relationship between stalk borer injury and loss of sugar. Various criteria and methods are compared. It is concluded that the ultimate loss in yield due to stalk borer infestation may be as large as 1% for each 1% joints bored, all forms of injury included.     

Calcium silicate enhances resistance of sugarcane to the African stalk borer Eldana saccharina Walker (Lepidoptera: Pyralidae)

Abstract

• 1 The stalk borer Eldana saccharina is the most destructive pest in sugarcane in South Africa. This study investigated: (1) the potential of applied silicon in enhancing plant resistance of sugarcane to E. saccharina, using calcium silicate as a carrier; (2) whether there was any interaction between cane variety (and stalk borer resistance) and silicon treatment.
• 2 Six commercial varieties of sugarcane were treated in a pot‐plant trial with two levels (5000 and 10 000 kg/ha) of calcium silicate. After artificial infestation with E. saccharina, response to the treatments was assessed in terms of borer numbers and mass, and stalk damage.
• 3 Calcium silicate significantly enhanced resistance at the higher rate compared with the control. Borer mass was reduced by 19.8% and stalk length bored by 24.4%. Lower treatment values were intermediate between those of the higher treatment and the control.
• 4 The interaction between variety and Si treatment was not significant when varieties were examined individually in the analysis. However, the interaction was significant for borer mass when varieties were grouped according to their resistance characteristics. Susceptible varieties might benefit more from treatment with silicon than resistant ones, as resistant varieties showed no significant effect of silicon.
• 5 All varieties had increased silicon content due to the treatments, but differed appreciably in stalk silicon content at the different treatment levels. Similarly, within varieties, stalk silicon content did not correspond consistently with borer response patterns and silicate application rates.

     

Sampling for the sugarcane borer (Lepidoptera: Crambidae) on sugarcane in Louisiana.

A 3-yr study was conducted in 0.6- to 2.0-ha sugarcane fields throughout south Louisiana under varying sugarcane borer, Diatraea saccharalis (F.), density levels to determine the spatial dispersion of infestations and to develop a sequential sampling plan. Infestations of D. saccharalis were randomly dispersed. Infestation levels (percentage of stalks infested) ranged from 0.6 to 33.3%. Frequency distributions of the number of infested stalks indicated that the Poisson distribution best fit the data Tests of other distributions (negative binomial [aggregated], binomial [uniform], geometric, and hypergeometric) resulted in poorer fits. The sequential sampling plan devised, with lower and upper D. saccharalis infestation limits of 2 and 5% and 5 and 10%, required maximum average sample numbers of 7.1 and 5.5 (20-stalk samples), respectively, to make terminating management decisions. It is our assessment that implementation of these plans would decrease sampling effort by 50-60% when compared with sampling programs currently in use for D. saccharalis management decisions in Louisiana.     

Lipids and fatty acids of the southwestern corn borer,Diatraea grandiosella

The lipids of the adults and of several immature stages of the southwestern corn borer, Diatraea grandiosella, were studied after they were fed natural corn stalks or artificial diets. Linoleic acid (18:2) was the major fatty acid of the neutral lipids in both the natural and the artificial diets, but aleic acid (18:1) was the principal neutral lipid in all insect stages. Also, linoleic acid and oleic acid were the principal acids in the insect phospholipids of all stages. The content of linoleic acid in the natural diet was also high, but that in the artificial diet appeared to be much too low for insect requirements. Phosphatidyl choline (PC) and phosphatidyl ethanolamine (PE) were the major phospholipids in all growth stages. Thus, in larvae diapausing in the field, the unsaturated fatty acid content of PC was 59·3 per cent, primarily 16:1 and 18:1, and PE was 87·4 per cent, primarily 18:1, 18:2, and 18:3, and the fatty acids in the number 1- and 2-positions of PC were 53·6 and 97·2 per cent unsaturated, respectively. The haemolymph of diapausing southwestern corn borer larvae contained primarily glycerides but also had some PC and PE. Fat body from diapausing larvae contained primarily 16:0, 16:1, and 18:1 in a ratio of 1 : 1 : 2. Thus lipids of the southwestern corn borer do not reflect dietary lipids as closely as do other insects studied.     

Establishment of Cry9C susceptibility baselines for European corn borer and southwestern corn borer (Lepidoptera: Crambidae)

In 1997 and 1998, Cry9C susceptibility baselines were established for field-collected populations of European corn borer, Osrinia nubilalis (Hubner), and southwestern corn borer, Diatraea grandiosella Dyar. Bioassay of neonate European corn borer larvae of 16 colonies collected from the midwestern United States indicated LC50 values ranging from 13.2 to 65.1 ng of Cry9C protein per square centimeter. Neonate European corn borer LC50 values ranged from 46.5 to 214 ng/cm2. Neonate larvae of three colonies of southwestern corn borer collected from the southern and southwestern United States exhibited LC50 values from 16.9 to 39.9 ng of Cry9C protein per square centimeter. Southwestern corn borer neonate LC90 confidence limit values ranged from 40.3 to 157 ng of Cry9C protein per centimeter. The most sensitive southwestern corn borer colony was collected from the Mississippi delta exhibiting an LC50 value of 22.6 ng of Cry9C per cm2 and also displayed the widest LC0 confidence limits of 40.3-94.8 ng of Cry9C per cm2. Geographic baseline susceptibility data establishes the natural genetic variation and provides the foundation for future testing of insect populations exposed to increased use of Bacillus thuringiensis-based crops. Insect resistance management and stewardship of Cry9C will rely upon baseline data for the validation of discriminating dose assays for European corn borer and southwestern corn borer.