Diatraea Saccharalis Fabricius Research Articles

Field-evolved resistance to Bt maize in sugarcane borer (Diatraea saccharalis) in Argentina.

BACKGROUNDMaize technologies expressing Bacillus thuringiensis (Bt) insecticidal proteins are widely used in Argentina to control sugarcane borer (Diatraea saccharalis Fabricius). Unexpected D. saccharalis damage was observed to Bt maize events TC1507 (expressing Cry1F) and MON 89034 × MON 88017 (expressing Cry1A.105 and Cry2Ab2) in an isolated area of San Luis Province. Diatraea saccharalis larvae were sampled from MON 89034 × MON 88017 fields in the area to generate a resistant strain (RR), which was subsequently characterized in plant and diet bioassays.RESULTSSurvivorship of the RR strain was high on TC1507 leaf tissue, intermediate on MON 89034 × MON 88017, and low on MON 810 (expressing Cry1Ab). The RR strain had high resistance to Cry1A.105 (186.74‐fold) and no resistance to Cry2Ab2 in diet bioassays. These results indicate resistance to Cry1F and Cry1A.105 (and likely cross‐resistance between them) but not to Cry1Ab or Cry2Ab2. Resistance to MON 89034 × MON 88017 was functionally recessive. Reviews of grower records suggest that resistance initially evolved to Cry1F, conferring cross‐resistance to Cry1A.105, with low refuge compliance as the primary cause. A mitigation plan was implemented in San Luis that included technology rotation, field monitoring, and grower education on best management practices (BMPs) including refuges.CONCLUSIONIn the affected area, the resistance to Cry1F and Cry1A.105 is being managed effectively through use of MON 89034 × MON 88017 and MON 810 in combination with BMPs, and no spread of resistance to other regions has been observed. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Resistance in 27 Rice Cultivars to Sugarcane Borer (Lepidoptera: Crambidae).

Rice (Oryza sativa L.) is considered one of the most important crops in the world, and the sugarcane borer, Diatraea saccharalis Fabricius (Lepidoptera: Crambidae), is among the key pests damaging the crop in the Americas. The objective of this work was to identify rice genotypes as a source of resistance to D. saccharalis. Rice plants were infested in the greenhouse and subsequently evaluated for damage, larval weight and survival, and stem size. The cultivars 'Bonança', 'Caripuna', 'IR 42', 'Canela de Ferro', 'SWA Norte', 'BR IRGA 409', 'Pepita', 'Serra Dourada', 'Araguaia', 'Xingú', 'Tangará', and 'Soberana' showed antibiosis antixenosis, or both to D. saccharalis. These cultivars may be used as donor sources in the breeding program and used directly by Brazilian farmers as a component of rice-integrated pest management.

Influence of historical land use and modern agricultural expansion on the spatial and ecological divergence of sugarcane borer, Diatraea saccharalis (Lepidoptera: Crambidae) in Brazil.

Human-mediated changes in landscapes can facilitate niche expansion and accelerate the adaptation of insect species. The interaction between the evolutionary history of the sugarcane borer, Diatraea saccharalis Fabricius, and historical and modern agricultural activity in Brazil shaped its spatial genetic structure, facilitating ecological divergence and incipient host shifting. Based on microsatellite data, STRUCTURE analyses identified two (K = 2) and three (K = 3) significant genetic clusters that corresponded to: (a) a strong signal of spatial genetic structure and, (b) a cryptic signal of host differentiation. We inferred that K = 2 reflects the footprint of agricultural activity, such as expansion of crop production (sugarcane and maize), unintentional dispersion of pests, and management practices. In contrast, K = 3 indicated incipient host differentiation between larvae collected from sugarcane or maize. Our estimates of population size changes indicated that a historical bottleneck was associated with a reduction of sugarcane production ≈200 years ago. However, a more recent population expansion was detected (>1950s), associated with agricultural expansion of large crop production into previously unfarmed land. Partial Mantel tests supported our hypothesis of incipient host adaptation, and identified isolation-by-environment (e.g., host plant) in São Paulo and Minas Gerais states, where sugarcane has been traditionally produced in Brazil. The impact of agricultural production on D. saccharalis may continue, as the current population structure may hinder the efficacy of refuge plants in delaying insect resistance evolution to Bt toxin.

Effects of single and multiple herbivory by host and non‐host caterpillars on the attractiveness of herbivore‐induced volatiles of sugarcane to the generalist parasitoid Cotesia flavipes

AbstractIt is well known that parasitoids are attracted to volatiles emitted by host‐damaged plants; however, this tritrophic interaction may change if plants are attacked by more than one herbivore species. The larval parasitoid Cotesia flavipesCameron (Hymenoptera: Braconidae) has been used intensively in Brazil to control the sugarcane borer, Diatraea saccharalisFabricius (Lepidoptera: Pyralidae) in sugarcane crops, where Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae), a non‐stemborer lepidopteran, is also a pest. Here, we investigated the ability of C. flavipes to discriminate between an unsuitable host (S. frugiperda) and a suitable host (D. saccharalis) based on herbivore‐induced plant volatiles (HIPVs) emitted by sugarcane, and whether multiple herbivory (D. saccharalis feeding on stalk + S. frugiperda feeding on leaves) in sugarcane affected the attractiveness of HIPVs to C. flavipes. Olfactometer assays indicated that volatiles of host and non‐host‐damaged plants were attractive to C. flavipes. Even though host‐ and non‐host‐damaged plants emitted considerably different volatile blends, neither naïve nor experienced wasps discriminated suitable and unsuitable hosts by means of HIPVs emitted by sugarcane. With regard to multiple herbivory, wasps innately preferred the odor blend emitted by sugarcane upon non‐host + host herbivory over host‐only damaged plants. Multiple herbivory caused a suppression of some volatiles relative to non‐host‐damaged sugarcane that may have resulted from the unaltered levels of jasmonic acid in host‐damaged plants, or from reduced palatability of host‐damaged plants to S. frugiperda. In conclusion, our study showed that C. flavipes responds to a wide range of plant volatile blends, and does not discriminate host from non‐host and non‐stemborer caterpillars based on HIPVs emitted from sugarcane. Moreover, we showed that multiple herbivory by the sugarcane borer and fall armyworm increases the attractiveness of sugarcane plants to the parasitoids.

Differential expression of the pr1A gene in Metarhizium anisopliae and Metarhizium acridum across different culture conditions and during pathogenesis.

The entomopathogenic fungi of the genus Metarhizium have several subtilisin-like proteases that are involved in pathogenesis and these have been used to investigate genes that are differentially expressed in response to different growth conditions. The identification and characterization of these proteases can provide insight into how the fungus is capable of infecting a wide variety of insects and adapt to different substrates. In addition, the pr1A gene has been used for the genetic improvement of strains used in pest control. In this study we used quantitative RT-PCR to assess the relative expression levels of the pr1A gene in M. anisopliae and M. acridum during growth in different culture conditions and during infection of the sugar cane borer, Diatraea saccharalis Fabricius. We also carried out a pathogenicity test to assess the virulence of both species against D. saccharalis and correlated the results with the pattern of pr1A gene expression. This analysis revealed that, in both species, the pr1A gene was differentially expressed under the growth conditions studied and during the pathogenic process. M. anisopliae showed higher expression of pr1A in all conditions examined, when compared to M. acridum. Furthermore, M. anisopliae showed a greater potential to control D. saccharalis. Taken together, our results suggest that these species have developed different strategies to adapt to different growing conditions.

Epicuticular hydrocarbons of the sugarcane borer Diatraea saccharalis (Lepidoptera: Crambidae)

The epicuticular hydrocarbons of the larval, pupal and adult stages of the sugarcane borer Diatraea saccharalis Fabricius (Lepidoptera: Crambidae) are analysed. Dramatic changes are observed between the stages studied. Adult hydrocarbons are mostly saturated, with a predominance of 1–4 methyl‐branched straight carbon skeletons of 37–47 atoms; the major components are isomeric mixtures of internally branched trimethylderivatives of C39, C37 and C41 carbon backbones. By contrast, very small amounts of methyl‐branched components are detected in the pupae, although straight chain hydrocarbons of 23–35 carbons are the prevailing structures (70.7 ± 3.4%) with n‐C29 and n‐C27 as the major components. Unsaturated hydrocarbons (29.0 ± 3.5%) of similar chain lengths elute by gas chromatography of epicuticular extracts as complex mixtures of mono‐, di‐ and trienes; with the degree of unsaturation increasing with chain length. This is the first report of very long chain unsaturated hydrocarbons in cuticular extracts of a larval lepidopteran (93.3 ± 0.6% of the lipid components), with chain lengths in the range 37–53 carbons and up to four double bonds; the major component being C49:3, which co‐elutes with C49:4 and C49:2.

Influence ofSaccharum officinarum(Poales: Poaceae) Variety on the Reproductive Behavior ofDiatraea flavipennella(Lepidoptera: Crambidae) and on the Attraction of the ParasitoidCotesia flavipes(Hymenoptera: Braconidae)

The aims of this laboratory-based study were: (1) to elucidate the reproductive behavior of Diatraea flavipennella Box in the presence of different sugarcane varieties, (2) to evaluate the capacities of Cotesia flavipes Cameron parasitoids raised on Diatraea saccharalis Fabricius and D. flavipennella to search for healthy and D. flavipennella-infested sugarcane varieties, and (3) to assess the response of the parasitoids towards volatiles released by healthy and D. flavipennella-infestea sugarcane plants. There were no significant differences (P ≥ 0.05) in calling, courtship, and copulation activities when D. flavipennella females, males, or couples were exposed to different sugarcane varieties. According to the number of egg masses and the total number of eggs oviposited, D. flavipennella females showed no preference for any sugarcane variety. The attraction of C. flavipes females to infested plants was significantly greater (P < 0.001) than to healthy plants, independent of the species of Diatraea on which the parasitoids had been reared. The number C. flavipes attracted to volatiles from infested sugarcane plants was significantly greater than those attracted to volatiles from healthy plants or to a hexane control (P < 0.001). It is concluded that none of the sugarcane varieties influenced the reproductive behavior of D. flavipennella, although the state of infestation of the host plants strongly influenced the response of C. flavipes.

Parasitism by the Endoparasitoid,Cotesia flavipesInduces Cellular Immunosuppression and Enhances Susceptibility of the Sugar Cane Borer,Diatraea saccharalistoBacillus thuringiensis

Cotesia flavipes Cameron (Hymenoptera: Braconidae), is a gregarious larval endoparasitoid of the sugarcane borer, Diatraea saccharalis Fabricius (Lepidoptera: Crambidae). The aim of this research was to analyze cellular immunosuppression of D. saccharalis parasitized by C. flavipes in terms of encapsulation, melanization, and hemocyte nodule formation. The encapsulation assay was done 1 and 6 days after parasitoid oviposition. In addition, the susceptibility of parasitized and nonparasitzed larvae to Bacillus thuringiensis HD 73 strain was assessed. 3, 12, and 24 h after bead injection; the percentages of encapsulation were significantly higher in unparasitized larvae compared to larvae parasitized 1 and 6 days after oviposition. Interestingly, there was a significant reduction in numbers of beads encapsulated at 1 day after oviposition compared to 6 days, and unparasitized larvae. The percentage of melanized beads decreased significantly in parasitized larvae compared to control. There was a reduction in the number of nodules in parasitized larvae compared to unparasitized controls. Larvae that were injected with polyndavirus 24 h before beads were injected showed significantly reduced encapsulation responses relative to control larvae. The D. saccharalis parasitized by C. flavipes exhibited higher susceptibility to B. thuringiensis. These results suggest that parasitization induced host immunosuppression, and the immunosuppression factors could impair the defense capacity against microbial pathogens - causing an increase in pathogen susceptibility.

Morphological regional differences of epithelial cells along the midgut in Diatraea saccharalis Fabricius (Lepidoptera: Crambidae) larvae

The sugarcane borer, Diatraea saccharalis Fabricius, is a pest to sugarcane and many other crops. This work aims to characterize morphological variability in the epithelial cells (columnar, goblet and regenerative) along the midgut of D. saccharalis larvae. Fragments of the midgut (anterior, middle and posterior regions) were fixed and processed by light and scanning electron microscopy. There are both cytochemical and ultrastructural differences in the morphology of the epithelial cells, depending on their localization along the midgut. The apical surface of columnar cells shows an increase in both number and size of the apical protrusions from the anterior to the posterior midgut regions. There is an increase in the amount of PAS-positive (Periodic Acid-Schiff Reaction) granules detected in the cytoplasm of both the columnar and regenerative cells, from the anterior to the posterior region. The goblet cell apical surface is narrow in the anterior region, and enlarged in the posterior midgut; the chamber's cytoplasm extrusion are small and thin at the apical cavity surface, being thicker, longer and more numerous at the basal portion of the cavity. Our results suggest that the sugarcane borer midgut has two morphologically different regions, the anterior and the posterior; the middle region is a transitional region.

Dieta artificial para criação de Doru luteipes (Scudder) (Dermaptera: Forficulidae), predador da lagarta-do-cartucho do milho, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

A new technique involving an artificial diet and an artificial substrate for oviposition for the rearing of the predator Doru luteipes (Scudder) is suggested. Both adults and nymphs were maintained in petri dishes containing a transparent piece of soda straw filled with moistened cotton and the corresponding food for the biossays. The following treatments were tested: eggs of Spodoptera frugiperda (J.E. Smith), Diatraea saccharalis Fabricius (Lepidoptera: Pyralidae) and Anagasta kuehniella Zeller (Lepidoptera: Pyralidae); insect pupae meal (FPI); Apis mellifera L. (Hymenoptera: Apidae) commercial pollen (PC); FPI + PC, and FPI + cattail pollen [Typha angustifolia L. (Thyphaceae)]. Each treatment had 50 replicates, and food was offered in excess. Treatments consisting of insect pupae meal (FPI), FPI + commercial pollen (PC), and FPI + cattail pollen resulted in nymphal development of 32, 29, and 29 days, with 83, 90 and 100% survival, respectively, and were superior to the PC treatment, with values of 37 days and 67% survival observed for insects reared on commercial pollen. Treatments that included insect pupae flour, either alone or mixed with pollens, were similar to control (S. frugiperda eggs). We conclude that the artificial diets tested and rearing technique are suitable for the artificial rearing of D. luteipes in laboratory conditions.

Laboratory and field tests of spray‐dried and granular formulations of a Bacillus thuringiensis strain with insecticidal activity against the sugarcane borer

Formulations of Bacillus thuringiensis Berliner (Bt) with insecticidal activity against the sugarcane borer, Diatraea saccharalis Fabricius (Lepidoptera: Pyralidae), were developed and tested under laboratory and field conditions. The formulations were prepared using biodegradable polymers such as modified corn starch as an encapsulating agent, gelatin as an adherent, powdered sugarcane as a feeding stimulant and a Bt var. kurstaki GM-34 strain from a non-sugarcane region as the active ingredient. The spore-crystal complex of this strain was mixed at three different concentrations (30, 70 and 100 g kg(-1)) with the other ingredients. The blends were prepared as spray-dried and granular formulations, and then submitted to laboratory tests with two day old larvae of D. saccharalis and field tests in sugarcane crops with natural sugarcane borer infestation. Spray-dried formulations in laboratory bioassays caused mortality near 100% with all three concentrations, and granular formulations caused mortality around 84%. The field tests showed that spray-dried formulations at 70 and 100 g kg(-1) concentrations were as effective as a commercial bioinsectide (Lepinox), while granular formulations were ineffective.

Morphometric study of the midgut epithelium in larvae of Diatraea saccharalis Fabricius (Lepidoptera: Pyralidae)

The sugarcane borer, Diatraea saccharalis Fabricius, has great economical interest as it affects the culture and industrial use of the sugarcane. However, there are few studies concerning the internal morphology of this insect. This work aims to study morphometrically the midgut and the epithelium along their lenght, trying to characterize different regions. Midgut of last instar larvae was divided in three regions: anterior, middle and posterior, and the fragments were processed for light microscopic observation. Histological sections were analyzed in a computerized system concerning the length, width and area of the epithelium, their cells, and the midgut lumen. The obtained data were statistically analyzed by the Kruskal-Wallis test and by multivariate analysis. Our results showed that the midgut has two different regions, the anterior and the posterior; the middle region presents values that are coincident with the ones of either the anterior and the posterior portions, suggesting that there is an intermediate region between the other two ones. The epithelial cells (columnar, goblet and regenerative cells), when evaluated by multivariate analysis, do not present significant morphometric differences in the different midgut regions. However, the analysis of variance for separate variables show that the regenerative cells present wide morphometric variability along the midgut.

Purification and characterization of three β-glycosidases from midgut of the sugar cane borer, Diatraea saccharalis

Three β-glycosidases, named βGly1, βGly2 and βGly3, were isolated from midgut tissues of the sugar cane borer, Diatraea saccharalis Fabricius (Lepidoptera: Pyralidae). The three enzymes have similar Mr (58,000; 61,000; 61,000), pI (7.5, 7.4, and 7.4) and optimum pH (6.7, 6.3, and 7.2) and were resolved by hydrophobic chromatography. The β-glycosidases prefer β-glucosides to β-galactosides, have four subsites for glucose binding and hydrolyse glucose-glucose β-1,3 linkages better than β-1, 4- or β-1,6 linkages. βGly1 and 2 were completely purified, whereas βGly3 was isolated with a contaminant peptide that has no activity upon β-glycosides. By using competing substrates, it was shown that βGly 1 and 3 have one active site, whereas βGly2 has two, one hydrolyzing natural and the other synthetic substrates. βGly2 is the only D. saccharalis β-glycosidase that can efficiently hydrolyse prunasin, the glycoside remaining after glucose removal from the plant glycoside amygdalin and that liberates the cyanogenic mandelonitrile. As shown elsewhere, βGly2 activity is reduced when D. saccharalis is reared in amygdalin containing diets. From the results, we propose that the physiological role of βGly 1 and 3 is the digestion of oligo- and disaccharides derived from hemicelluloses and of βGly2 is glycolipid hydrolysis. Free energy relationships showed that D. saccharalis βGly3 and Tenebrio molitor (Coleoptera) βGly1 have active sites that bind similarly the transition states formed with different substrates. The same is also true for the active sites of D. saccharalis βGly1 and T. molitor βGly2. This suggests that active sites of similar enzymes are probably homologous, displaying nearly identical bonds between active site amino acids and substrate moieties.

Fall armyworm (Lepidoptera: Noctuidae), southwestern corn borer (Lepidoptera: Pyralidae) and sugarcane borer (Lepidoptera: Pyralidae) damage and grain yield of four maize hybrids in relation to four tillage systems

Zero tillage can be used tactic to prevent soil erosion and save the top soil for maize production.The effects of tillage systems on the growth, grain yield and resistance of maize hybrids against fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), sugarcane borer (SCB), Diatraea saccharalis Fabricius and southwestern corn borer (SWCB), Diatraea grandiosella (Dyar) were examined. Four single cross hybrids used were: Ki3×CML139 (resistant), Ki3×CML131 (susceptible), CML67×CML135 (resistant) and Ki3×CML69 (susceptible). These hybrids were sown on land with conventional tillage, minimum tillage and zero tillage, with and without mulch, in infested and insecticide—protected plots. The resistance/susceptibility of these hybrids against FAW, SCB and SWCB was not altered by the tillage systems. Hybrids planted under zero-tillage+mulch suffered significantly higher damage by SCB and FAW probably because of the retention of moisture in the mulch, which provided optimum conditions for larval feeding. Damage by SWCB on hybrids was the same in different tillage systems because of relatively dry conditions prevailing in the trial. Grain yield of the four hybrids was generally higher in zero-tilled plots in comparison to conventional or minimum tillage systems. These observations support the use of zero-tillage for maize production. Data also show that FAW infestation at 4–5 leaf stage caused grain yield reduction of 10–13% across all tillage systems in the tropical environment but in a subtropical environment, yield reduction was only 1–2%. Grain yield of the hybrids Ki3×CML139 and Ki3×CML69 was affected by SCB infestation in all the tillage systems but that of CML67×135 and Ki3×CML131 was not affected. SWCB infestation on the hybrid Ki3×CML131 was less in the infested plots but that of remaining hybrids was the same in infested and protected plots in different tillage systems. Thus, zero-tillage can be used on community-wide basis to prevent the soil erosion and save our dwindled soil resources.

QTL Mapping in Tropical Maize: III. Genomic Regions for Resistance to Diatraea spp. and Associated Traits in Two RIL Populations

The southwestern corn borer (SWCB, Diatraea grandiosella Dyar) and sugarcane borer (SCB, Diatraea saccharalis Fabricius) are two related insect species that cause serious damage in maize production in subtropical and tropical regions of Central and Latin America. We analyzed quantitative trait loci (QTL) involved in resistance to the first generation of both borer species in two recombinant inbred line (RIL) populations from crosses CML131 (susceptible) × CML67 (resistant) and Ki3 (susceptible) × CML139 (resistant). Resistance was evaluated as leaf feeding damage (LFD) in replicated field trials across several environments under artificial infestation. Leaf protein concentration and leaf toughness were evaluated in one environment as putative components of resistance. The method of composite interval mapping was employed for QTL detection with RFLP linkage maps derived for each population of RIL. Estimates of the genotypic and genotype × environment interaction variances for SWCB LFD and SCB LFD were highly significant in both populations. Heritabilities ranged from 0.50 to 0.75. In Population CML131 × CML67, nine and eight mostly identical QTL were found for SWCB LFD and SCB LFD, respectively, explaining about 52% of the phenotypic variance () for each trait. In Population Ki3 × CML139, five QTL for SWCB LFD were detected, explaining 35.5% of . Several of these QTL were found in regions containing QTL for leaf protein concentration or leaf toughness. A low number of QTL in common between the two RIL populations and between RIL and corresponding populations of F2:3 indicated that the detection of QTL depended highly on the germplasm and population type. Consequently, chances of successful application of marker‐based selection (MBS) for corn borer resistance are reduced when QTL are not identified in the germplasm in which the final selection will be carried out.

QTL Mapping in Tropical Maize: I. Genomic Regions Affecting Leaf Feeding Resistance to Sugarcane Borer and Other Traits

Sugarcane borer (SCB), Diatraea saccharalis Fabricius, is a serious pest in tropical maize production areas in the Americas. Little is known about the genetic resistance of maize genotypes to this pest. In this study, we mapped and characterized quantitative trait loci (QTL) affecting resistance to the leaf feeding generation of SCB (1SCB), grain yield under both protection (GYP) and infestation (GYI) with SCB larvae, and plant height (PITT). A total of 171 F2 genotypes derived from cross CML131 (susceptible) × CML67 (resistant) 93 RFLP marker loci were used in QTL analyses. F3 lines were evaluated for the above traits and grain yield reduction (GYR) in field experiments with two replications at two or three tropical environments. Resistance was assessed by rating leaf feeding damage after artificial infestation with SCB larvae. The method of composite interval mapping with selected markers as cofactors was used for detection and characterization of QTL. Resistance to 1SCB was significantly affected by 10 putative QTL on Chromosomes 1, 2, 5, 7, 8, 9, and 10. These showed predominantly additive gene action and explained 65.0% of the phenotypic variance and 93.5% of the genetic variance in a simultaneous fit. Six QTL for GYP, five QTL for GYI with primarily dominant genetic effects, and four QTL for PHT with primarily additive genetic effects were identified, explaining in total about one third of the phenotypic variance for the respective trait. No more than one putative QTL was found to be common between different characters. QTL × environment interaction was found to be significant for 1SCB ratings only. Based on these data, prospects for improving 1SCB resistance by marker‐assisted breeding are promising.

Resistance in maize hybrids and inbreds to first-generation southwestern corn borer, Diatraea grandiosella (Dyar) and sugarcane borer, Diatraea saccharalis Fabricius

The mechanisms of resistance in three maize hybrids and five CIMMYT maize lines (CML) to southwestern corn borer (SWCB) Diatraea grandiosella Dyar (Lepidoptera: Pyralidae) and sugarcane borer (SCB) Diatraea saccharalis Fab. (Lepidoptera: Pyralidae) were studied in the field and laboratory. The SWCB infests maize in the high latitude and mid-altitude areas and SCB infests maize in the lowland tropical areas in Mexico. The hybrids tested were Ki3 × CML131, CML67 × 135 and CML139 × 135, and the inbreds tested were Ki3, CML67, CML131, CML135 and CML139. Nonpreference and/or antibiosis were the mechanisms of resistance expressed by the hybrids CML67 × 135 and CML139 × 135 grown in the fields as indicated by the low leaf feeding damage, low larval survival of the two species. The resistance in the two resistant hybrids evidently came from the resistant inbreds CML67 and CML139 because the parameters measured for non-preference and antibiosis were also very low in these resistant inbreds in comparison to CML131, Ki3 and CML135. Laboratory studies also indicated that feeding non-preference and/or antibiosis was the first line of defence in the resistant hybrids (CML67 × 135 and CML139 × 135) and inbreds (CML67 and 139) against the attack of stem borers. The survival and growth of the larvae were then adversely affected because of antibiosis in resistant plants to two species of borers. Because of non-preference and antibiosis mechanisms of resistance, the hybrids CML67 × 135 and CML139 × 135 suffered little from leaf and stalk damage, and thus lost little grain yield (3–4%) in comparison to the susceptible hybrid Ki3 × CML131 (35–40%) under heavy infestation by the SWCB and SCB in the fields. These resistant hybrids can be readily used in the integrated pest management (IPM) programs under subsistance farming conditions in the subtropical and tropical environments to reduce yield reductions and increase food production, if grain color, texture, taste and grain quality are acceptable.

Nematodes Parasitic on Diatraea Saccharalis Fabricius in Cuba

Journal Article Nematodes Parasitic on Diatraea Saccharalis Fabricius in Cuba Get access H. K. Plank H. K. Plank Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Economic Entomology, Volume 22, Issue 6, 1 December 1929, Pages 982–983, https://doi.org/10.1093/jee/22.6.982 Published: 01 December 1929

Natural Enemies of the Sugar Cane Moth Stalkborer in Cuba1

The habit which the sugar cane moth stalkborer ( Diatraea saccharalis Fabricius) has of spending the greater part of its life in tunnels in the stalks of sugar cane, corn, and certain grasses serves as an admirable protection against direct, or artificial, measures of control (9),[2][1] but does not seem to afford any great amount of protection against the attack of a rather formidable array of natural enemies. Such a condition is indicated in the comprehensive list of sugar cane moth borer parasites recently published by Van Dine (13). In this list, which includes the parasites reported from different parts of the world, there are ten species credited to Cuba. Among these is Bassus ( Microdus ) stigmaterus , described by Cresson from Cuba in 1865 (2), and reported by Holloway and others (3, 5) as being a parasite of Diatraea saccharalis , as well as four other species reported by Cardin in 1915 (1). Since 1915 the remaining five species have been reported by various authors. [1]: #fn-2