Postharvest Pests Research Articles

Genetic diversity analysis in tropical maize germplasm for stem borer and storage pest resistance using molecular markers and phenotypic traits

One hundred maize inbred lines and eighty four hybrids were characterized for resistance to maize stem borer and post-harvest insect pests. This was achieved using genetic distance and population structure based on simple sequence repeat (SSR) markers and biophysical traits. The test materials were evaluated for stem borer, maize weevil and larger grain borer (LGB) resistance. Leaf samples were harvested from 10 healthy plants per genotype and bulked. Genomic DNA was extracted using a modified version of mini-prep Cetyl Trimethyl Ammonium Bromide (CTAB) method. The samples were genotyped with 55 SSRs makers. Univariate analysis of variance was done using the general linear model procedure of SAS statistical package. Rodgers genetic distance was calculated for all data sets as a measure of genetic distance using NTSYS-pc for Windows. The distance matrices were used to generate phenograms using the unweighted pair group method based on arithmetic average (UPGMA) method in MEGA5. The genotypes were assigned into different populations using population structure software. The data was further subjected to discriminant and principal component analysis to group the gnotyoes. Analysis of molecular variance within and among the different populations was done using arlequin. There were significant differences (P ≤ 0.001) for all the biophysical traits evaluated. The SSR marker data estimated successfully the close relationship among different hybrids and inbred lines within clusters. Comparisons of the different multivariate analyses revealed high concordance among the different approaches of analyses. The results of this study can be directly used by breeding programs to develop resistant genotypes.

Phytochemical and Nutraceutical Changes during Recurrent Selection for Storage Pest Resistance in Tropical Maize

ABSTRACTMaize (Zea mays L.) is a staple crop used for subsistence by smallholder farmers around the world, who usually store grain for gradual use. During the course of storage, losses due to storage pests often reach 20%. Over three cycles of recurrent selection, population improvement to develop sources of resistance to the larger grain borer (Prostephanus truncates) and the maize weevil (Sitophilus zeamais) resulted in a new population called Population 84 (P84). The objective of this study was to evaluate the biophysical, phytochemical, and nutraceutical profile changes in P84 derived from three cycles of selection for resistance. Insect resistance parameters were evaluated using bioassay and biophysical, phytochemical, and nutraceutical parameters. Resistance to storage pests increased by two‐ to threefold after three cycles of selection for maize weevil and larger grain borer, respectively. The major factors related to enhanced resistance are kernel hardness (10% increase) and proportion of pericarp (68% increase) in the kernel. Comparing the phytochemical composition of the pericarp cell wall before and after selection revealed an elevated level of cell wall–bound components (42% increase), including ferulic and diferulic acids (14% and twofold increase, respectively). Increases of 18% in free phenolic acid were found in the endosperm. A significant association between insect resistance with antioxidant activity (r > 0.75) establishes the possibility of seeking increased nutrients beneficial for human health in the same maize germplasm selected for increased insect resistance and stemming from the same compounds. Population 84 is a good source for resistance to postharvest pests with enhanced nutraceutical properties.

Comparing genetic diversity of Sitophilus zeamais (Motchulsky) popula-tions sampled in several agro-ecological areas between Central African Republic and Senegal

Maize is attacked by many post-harvest pests including Sitophilus spp and Prostephanus spp, which causes remarkable loss during storage. Approxi-mately 30 to 40 % loss in the absence of treatment has been reported world-wide. This study compare genetically Central African and Senegalese popula-tions of Sitophilus zeamais from various agroecological zones using 3 mark-ers namely cytochrome b, cytochrome oxidase and nuclear 28S gene. S. zeamais samples were analyzed on both of two other sites 34 for the 28S gene; 68 for cytochrome b and 36 for the cytochrome oxydase. Results ana-lyzed by AMOVA have shown high genetic variation outside population of each country (6.17 % with Cyt b; 21.45 % with 49.83 % and COI in the case of 28S) and low within subpopulations (-10.06 % for Cyt b, 9.36 % for the COI and -15.23 % for 28S). Majority haplotype is shared between the two popula-tions for 28S and cytochrome b genes and there is a very high haplotype di-versity in populations of Senegal considering the Cytochrome b gene (0.781 + / - 0.00364) while with COI and 28S, high values of diversity are observed in Central African sequences, respectively 1.000 + / - 0.00274 and 0.867 + / - 0.011. Genetic differentiation obtained according to the geographical origin is significant between the two populations; however, it is not at the level of subpopulations. Developed by the three approaches (parsimony, likelihood and Bayesian) phylogenetic trees are resolved and show a speciation of the two populations according to the geographical origin.

Bioactive metabolites of Senna didymobotrya used as biopesticide against Acanthoscelides obtectus in Bungoma, Kenya

Post-harvest pests are known to cause severe losses of beans in particular the bean weevil, Acanthoscelides obtectus, necessitating immediate and long term control measures. Convectional pesticides have been used for decades to protect stored grain from pests, but their harmful environmental impact and pest resistance resulting from the need for increased pesticide use have triggered researchers to search for eco-friendly, biodegradable and potent biopesticides. The use of natural products derived from metabolic activity of plants may constitute a new avenue of pest control. This paper describes phytochemical and biological investigations of leaves, root, and stem bark crude extracts and isolated compounds of selected Kenyan plants used to control the bean weevil. Bioassays tests of the compounds were done against brine shrimp to test their insecticidal activity against the bean weevil. Antibacterial and antifungal activity of the crude extracts of S. didymobotrya was also done. The extracts of S. didymobotrya showed high toxicity as well as adulticidal activity against bean weevil.

Oxygenated phosphine fumigation for control of Epiphyas postvittana (Lepidoptera: Tortricidae) eggs on lettuce.

Light brown apple moth, Epiphyas postvittana (Walker), is a quarantined pest in most countries. Its establishment in California and potential spread to other parts of the state and beyond make it urgent to develop effective postharvest treatments to control the pest on fresh commodities. Fumigation with cylindered phosphine at low temperature has emerged to be a practical methyl bromide alternative treatment for postharvest pest control on fresh commodities. However, its use to control E. postvittana eggs on sensitive commodities such as lettuce is problematic. E. postvittana eggs are tolerant of phosphine and long phosphine treatment also injures lettuce. In the current study, E. postvittana eggs were subjected to oxygenated phosphine fumigations to develop an effective treatment at a low storage temperature of 2 degrees C. In addition, soda lime as a CO2 absorbent was tested to determine its effects in reducing and preventing injuries to lettuce associated with phosphine fumigations. Three-day fumigation with 1,000 ppm phosphine under 60% O2 achieved 100% mortality of E. postvittana eggs in small-scale laboratory tests. In the presence of the CO2 absorbent, a 3-d large-scale fumigation of lettuce with 1,700 ppm phosphine under 60% O2 resulted in a relative egg mortality of 99.96% without any negative effect on lettuce quality. The 3-d fumigation treatment without the CO2 absorbent, however, resulted in significant injuries to lettuce and consequential quality reductions. The study demonstrated that oxygenated phosphine fumigation has the potential to control E. postvittana eggs and the CO2 absorbent has the potential to prevent injuries and quality reductions of lettuce associated with long-term oxygenated phosphine fumigation.

Postharvest physiology and technology of Spondias purpurea L. and S. mombin L

Spondias purpurea and S. mombin (Anacardiaceae) are tropical species native to Mexico with a distribution that spans all of tropical America, Central America, Peru and Brazil. The fruits are consumed fresh or processed and enjoy good consumer acceptance because of their taste, which ranges from sour to sour-sweet, and in the case of S. purpurea because of the diversity of colouration of its epicarp. All of these characteristics suggest a high commercial potential for Spondias in Mexico and other regions of tropical America, as well as in export markets. Despite this, the marketing of fruits is mainly local due to their high perishability. The most common postharvest pests and diseases are fruit flies and fruit-rot fungi; however a limited number of conservation methods are used because of the scarce knowledge concerning the postharvest physiological behaviour of Spondias fruit. This document therefore, aims to provide relevant information about the biology and postharvest technology of S. purpurea and S. mombin published by other authors over the last 50 years, as well as experimental data obtained by our research group that will provide a useful reference for future work on the postharvest handling of these genetic resources.

Molecular markers reveal narrow genetic base and culturing-associated genetic drift inTeretrius nigrescensLewis populations released for the biological control of the larger grain borer in Africa

In biological control, successful establishment of a natural enemy species depends on its adaptability in the introduced range including its ability to re-establish desired ecological interactions with the pest. These are affected by genetic parameters hitherto largely unresolved in biological control. The larger grain borer (LGB), Prostephanus truncatus, an invasive species from meso-America, is the most important post-harvest pest of maize in Africa. We studied the genetic structure of Teretrius nigrescens, a predatory beetle previously released for the control of the pest in Africa, to test the hypothesis that establishment patterns were a result of ecotype-environment mismatch and to follow up on our earlier reports of distinct lineages of the predator. We studied 13 populations of T. nigrescens, using 16 polymorphic microsatellite markers. Five genetic populations with a hierarchical structure and significant isolation by distance were detected. The most diverse population was found in southern Mexico, consistent with earlier lineage coexistence observations. Populations introduced to Africa maintained genetic similarity to local geographic populations of their area of origin. The more successful Benin releases were also more genetically diverse. Loss of rare alleles and a higher frequency of existing private alleles in some populations indicated population expansions following bottleneck events. Sustainable biological control should accommodate pest and natural enemy species, and monitor genetic changes associated with introduction and release.

Nitric Oxide as a Potent Fumigant for Postharvest Pest Control

There is a great demand for safe and effective alternative fumigants to replace methyl bromide and other toxic fumigants for postharvest pest control. Nitric oxide, a common signal molecule in biological systems, was found to be effective and safe to control insects under ultralow oxygen conditions. Four insect species including western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera Thripidae); aphid, Nasonovia ribisnigri (Mosley) (Homoptera: Aphididae); confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae); and rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae), at various life stages were fumigated with 0.1-2.0% nitric oxide under ultralow oxygen levels of < or = 50 ppm in 1.9-liter glass jars at 2-25 degrees C depending on insect species. Fumigations were effective against all four insect species. Efficacy of nitric oxide fumigation increased with nitric oxide concentration, treatment time, and temperature. There were also considerable variations among insect species as well as life stages in susceptibility to nitric oxide fumigation. Complete control of thrips was achieved in 2 and 8 h with 2.0 and 0.2% nitric oxide, respectively, at 2 degrees C. At the same temperature, complete control of the aphid was achieved in 3, 9, and 12 h with 1.0, 0.5, and 0.2% nitric oxide, respectively. Larvae, pupae, and adults of confused flour beetle were effectively controlled in 24 h with 0.5% nitric oxide at 20 degrees C. Complete mortality of confused flour beetle eggs was achieved in 24 h with 2.0% nitric oxide at 10 degrees C. Rice weevil adults and eggs were effectively controlled with 1.0% nitric oxide in 24 and 48 h, respectively, at 25 degrees C. These results indicate that nitric oxide has potential as a fumigant for postharvest pest control.

Postharvest Control of Western Flower Thrips (Thysanoptera: Thripidae) and California Red Scale (Hemiptera: Diaspididae) With Ethyl Formate and Its Impact on Citrus Fruit Quality

The postharvest control of arthropod pests is a challenge that the California citrus industry must overcome when exporting fruit overseas. Currently, methyl bromide fumigation is used to control postharvest pests on exported citrus, but it may soon be unavailable because of use restrictions and cost of this health-hazard ozone-depleting chemical. Ethyl formate is a natural plant volatile and possible alternative to methyl bromide in postharvest insect control. The objectives of this study were 1) to evaluate the mortality of third instar California red scale [Aonidiella aurantii (Maskell)] (Hemiptera: Diaspididae) and adult western flower thrips [Frankliniella occidentalis (Pergande)] (Thysanoptera: Thripidae) under a wide range of ethyl formate concentrations, 2) to determine the ethyl formate concentration required to reach a Probit 9 level of control for both pests, and 3) to test the effects of ethyl formate fumigation on the quality of navel oranges [Citrus sinensis (L.) Osbeck] and lemons [Citrus limon (L.) Burman f.] at 24 h after fumigation, and at different time periods to simulate shipping plus storage (5 wk at 5 degrees C), and shipping, storage, handling, and shelf-life (5 wk at 5 degrees C, plus 5 d at 15 degrees C, and 2 d at 20 degrees C). The results indicate that ethyl formate is a promising alternative to methyl bromide for the California citrus industry, because of successful control of adult western flower thips and third instar California red scale and no deleterious effect on fruit quality at any of the evaluated periods and quality parameters.

Repellent effects of essential oils from selected eucalyptus species and their major constituents against Sitophilus zeamais (Coleoptera: Curculionidae)

Maize (Zea mays L.) is Kenya's most important staple crop with annual production fluctuating between 2.6 and 3.1 million tons in 2012 and 2011, respectively. However, frequent food shortages are still experienced in the country. These have been attributed to pests and diseases and post-harvest constraints. The dominant post-harvest pest of maize is Sitophilus zeamais (Motsch.), which causes losses between 10 and 20% of harvested grain. The objective of this study was to establish the repellent activity of essential oils extracted from selected eucalyptus species against S. zeamais. Essential oils were extracted from the fresh leaves of Eucalyptus saligna Sm., Eucalyptus globulus Labill., Eucalyptus camaldulensis Schlecht and Eucalyptus citriodora Hook by steam distillation using a Clevenger-type apparatus. A repellency bioassay, with varying concentrations (0.002, 0.02, 0.2 and 2 μl/μl) of the oils, was carried out against the maize weevils using a Y-shaped olfactometer. Repeated measures of analysis of variance were applied to test the different doses and repellents, and their interactions against S. zeamais. The essential oils of E. camaldulensis and E. citriodora presented better repellent activity at the 2 μl/μl concentration (74.35 and 69.15%, respectively) followed by those of E. globulus (53.68%) and E. saligna (40.5%). Gas chromatography (GC)–mass spectrometry and GC co-injections with authentic samples showed the presence of the following major constituents in: (i) E. camaldulensis oil: 1,8-cineole (18.9%), α-cardinol (6.4%) and β-phellandrene (2.6%); (ii) E. citriodora oil: 1,8-cineole (11.2%), β-pinene (3.2%) and 4-terpineol (3.1%); and (iii) E. globulus oil: 1,8-cineol (17.2%), α-pinene (7.1%) and spathulenol (6.5%). The results provide a scientific rationale for the use of eucalyptus oils in the protection of maize against weevils.

Storage of open-pollinated maize variety seeds in active cattle kraal to suppress maize weevils and improve seed quality and seedling vigour

Open-pollinated maize (Zea mays) varieties remain popular in marginal communities since seeds can be selected and stored for the next season. However, maize weevil (Sitophilus zeamais) is an economic post-harvest pest of maize grains, which is difficult to manage. Various indigenous seed storage technologies had been in use within marginal communities, with little empirically-based support of their efficacy on weevils. The influence of storing maize seeds in active cattle kraal (ACK) for suppression of weevils and therefore protection of seeds was studied at three locations over two seasons. Water-tight plastic containers, each with 500 maize seeds infested with 20 maize weevils, with 10 replications, were stored in 30-cm-deep holes in ACK, with controls stored at farmer level. At 120 days after storage, relative to farmer controls, ACK reduced final S. zeamais numbers (73 to 95%) and damage of various seed sets (27 to 97%), but improved seed quality (101 to 3500%), seedling emergence (27 to 64%) and root/shoot ratio (19 to 50%). In conclusion, results of the study suggested that ACK storage has the potential for storing open-pollinated maize seeds throughout winter for farmers in marginal communities to allow for quality seeds that produce vigorous seedlings in the next growing season. Key words: Active cattle kraal, maize weevil, Sitophilus zeamais, seed quality, seedling vigour.

Sources of Resistance to the Maize Weevil Sitophilus Zeamais in Tropical Maize

The maize weevil, Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae), is among the major storage pests that enhance food insecurity among maize farmers. New sources of resistance to the maize weevil are critical in a successful breeding program to address grain damage by postharvest pests. The objective of the study was to evaluate resistance in maize genotypes to the maize weevil, and consequently their value for use in breeding programs. A total of 175 genotypes, including hybrids, landraces, open-pollinated varieties and checks, were tested for resistance to the maize weevil. The percentage grain damage, weight loss, flour weight and weight of damaged and undamaged grains were measured. Significant differences (P <0.001) were observed among the genotypes for all the traits evaluated. The distribution of the genotypes among the different categories of resistance was an indication of the existence of genetic variation. The most resistant genotypes were CKPH08003 and BRAZ 2451 while the most susceptible were PH 3254 and BRAZ 4, among the hybrids and landraces respectively. Genotypes that were superior to the resistant checks were identified. The percentage weight loss and flour weight were identified as the most important insect-resistance traits for discriminating genotypes as evident from the canonical discriminant analysis. Correlation coefficients among the traits evaluated were highly significant. The resistant hybrids identified can be recommended for release and adoption by farmers, whereas the resistant landraces can act as sources of resistance for use in breeding programs.

Insecticidal Effect of Fruit Extracts from Xylopia aethiopica and Dennettia tripetala (Annonaceae) against Sitophilus oryzae (Coleoptera: Curculionidae)

The insecticidal and repellent activities of fruit extracts of Xylopia aethiopica (Dunal) A. Rich. and Dennettia tripetala (Baker f.) G.E. Schatz belonging to the family Annonaceae was studied against Sitophilus oryzae (L.), an economic, primary post-harvest pest of rice, and other cereal products. Infested rice grains (100 g) treated with 1, 2, 3, 4, and 5% (w/w) powders of both plants were evaluated for toxicity against S. oryzae every 24 h for 3 d, and during F1 progeny emergence. The essential oils of both plants were also applied at 0.5, 1, 1.5 and 2 mg cm-2 filter paper in Petri dishes for toxicity bioassays at 24 h exposure. Repellence bioassay with 10 μL solution of essential oils on filter paper was performed in a Y-Tube airflow olfactometer. Results indicate that powders of both plants significantly (P < 0.001) caused adult weevil mortality and a reduction in F1 progeny emergence than the control. Essential oils were also significantly (P < 0.001) adulticidal to S. oryzae after 24 h with the highest dose (2 mg cm-2) producing 100% mortality respectively. Similarly, both male and female weevils significantly avoided the test arm compared to the control arm in the Y-Tube olfactometer repellence tests. These results suggest that X. aethiopica and D. tripetala natural extracts have potential for use as part of integrated pest management of stored product protection against S. oryzae.

TABEL HIDUP Sitophilus oryzae (Coleoptera; Curculionidae) PADA BERAS

ABSTRACT The problem in postharvest pests must be handled seriously since recent research were not comprehensively resolved it. Sitophilus oryzae was a major pest and serious problem on post harvest products. The reseach aimed to develop a life table of S. oryzae on rice. The life table is a part of life history that consists of important information about the living organism. This information can be used for predicting population growth. By developing life table database, information on mortality, life expectancy, and the development ability of S. oryzae can be obtained. Results showed that mortality index of eggs was 0.4; larvae was 0,54, and pupae was 0,32, and adult was 1,0. Life expectancy index of eggs was 1.65; larvae was 1.42; pupae was 1.51 pupae; and adults was 1.0. One female was able to give rise 32.56 females or 58.57 males and females of the next generation. Keywords : Life table, Sitophilus oryzae, mortality index, life expectancy

The positive contribution of invertebrates to sustainable agriculture and food security.

Abstract This study focuses on three main groups of organisms: soil invertebrates, biological control agents (BCAs) and pollinators. These groups play key roles in agricultural systems, and have the potential to be used, moved or manipulated for the benefit of agriculture. Soil invertebrates are a key component of agricultural landscapes. They participate in essential soil processes that maintain healthy productive soils in the face of changing environmental conditions. Reducing the diversity of a community of soil invertebrates reduces its beneficial functions and services, with drastic ecological effects such as long-term deterioration of soil fertility and agricultural productive capacity. The introduction of a keystone species may have detrimental or beneficial effects depending on the context. The interaction between soil invertebrates and soil micro-organisms is critical: the activities of soil invertebrates regulate microbial activity in soils, and micro-organisms enter into intimate relationships with soil invertebrates to help them degrade highly complex compounds such as cellulose. Different groups of invertebrates provide biological control of crop pests. In many situations, they form the basis of, and tools for, the integrated pest management (IPM) approach. Given that the losses caused by pre- and post-harvest pests can be very substantial, the potential benefits of using invertebrates as BCAs are vast, but as yet only partially tapped. The potential for soil invertebrates to assist in this function is still largely unknown. Pollination services by animals, especially by insects, are among the most widespread and important processes that structure ecological communities in both natural and agricultural landscapes. An estimated 60-90% of the world's flowering plants - including a range of economically important species - depend on insects for pollination. Crop pollination used to be (and often still is) provided by wild pollinators spilling over from natural and semi-natural habitats close to crop fields. This service has generally been free and therefore has received little attention in agricultural management. If wild pollinators are lacking or additional pollination is required, as is the case in many intensive agricultural production systems, farmers in some developed countries can buy or rent managed honeybees or sometimes other species (e.g. bumblebees, alfalfa leafcutter bees and alkali bees). Both options - i.e. use of wild species and managed bees - have recently come under pressure, a development that is sometimes referred to as the 'pollination crisis'. Of the interactions and overlaps between these key groups, that between soil invertebrates and BCAs is the most important, and further research is needed to evaluate the scope and impact of manipulation of the soil ecosystem to conserve or encourage beneficial BCAs.

Adoption of Integrated Pest Management (IPM) in Chilli (Capsicum annuum L.): A Case Study from Guntur District, Andhra Pradesh

An Integrated Pest Management (IPM) project was implemented in the cropping season 2006-07 in six villages of Guntur District. Survey was conducted in the six villages and all 150 chilli farmers participating in Crop Life India (CLI) sponsored IPM project were treated as a sample for the study. In the case of sucking pests, 56% of the farmers expressed that mites were an important pest. Among the fruit borers, a majority (83.33%) felt that Spodoptera litura was a serious problem and; among diseases, 56% opined die-back to be the major problem. More than twothirds of the respondents adopted all components of IPM, with the exception of bioagents where adoption was just 46%. 44% felt leaf spot was a major disease. Over 80% adopted border crops, trap crops, scouting techniques and mechanical-control measures. All the respondents followed 10-15 day pre-harvest interval of pesticide application as a measure for obtaining quality produce and better price. Problems of post-harvest pests and diseases were not observed in the case of well-dried chillies.

Biological effects of three Annona species on Callosobruchus chinensis: A green alternative for storage pest management

Plants have been known as a rich source of bioactive chemicals. These have been exploited in insect-pest management strategies as repellents, feeding deterrents, ovipositional deterrents and in many other ways in the biology of insects. The possible use of Annona species as eco-friendly alternatives to synthetic insecticides for the management of Callasobrucus chinensis in legumes was investigated from this perspective. In the present study, methanol extracts of leaves of Annona squamosa (Sugar apple), A. reticulata (Custard apple), and A. glabra (Pond apple) were evaluated to determine their effects on the oviposition, egg incubation and hatchability of C. chinensis. The effect of leaf extracts on the viability of cowpea seeds was also determined. Three doses (2.5, 7.5 and 12.5g/l) of leaf extracts were used in all tests. All the extracts tested resulted in significant reduction in oviposition in females. This reduction was dose-dependent and increased with the increase of dosage. Extracts of A. squamosa induced significantly the highest oviposition deterrence of 49.4% in the insects at the highest dose of 12.5g/l. A. reticulata (42.5%) and A. glabra (32.3%) on the other hand caused respectively lower deterrence. No deterrence of oviposition (0.0%) was observed with the control. In contrast, egg hatchability decreased with the increase of the dosage of extracts. A. squamosa at the highest dose evoked the lowest percentage egg hatch (35.2%) while 96.4% eggs hatch was observed with the control. Egg hatchabilty caused by A. reticulata extract at the same dose was 70.3% which was twice as much observed with A. squamosa. Furthermore, incubation period of eggs also increased with time and dose. In comparison to the control (4.0 days), the highest incubation period was recorded from eggs treated with A. glabra at the dose of 12.5g/l (7.7 days) followed by A. squamosa (6.9 days). None of the plant extracts elicited any adverse effects on the germination capability (viability) of cowpea seeds which varied between 99-100%. The overall results of the study indicate that all three Annona species have a positive impact on the management of this beetle. Moreover, A. squamosa could be considered as the most effective compared to the other two species. As all three plant species tested are locally available, the outcome of this study may certainly help in paving the way for their usage against post-harvest pests.

Some biological characteristics of the Batrachedra amydraula Meyrick (Lepidoptera: Batrachedridae) on main varieties of dry and semi-dry date palm of Iran

Although Iran is the leading producer of dates in the world, only 10% of its product is exported. One of the factors which limits exportation is postharvest pests. Lesser date moth ( Batrachedra amydraula ) is one of these postharvest pests. This pest is found in all date palm plantations of Iran. The biology of this pest has not been studied under laboratory conditions on main varieties of stored date in Iran. In this research some biological characteristics including survivorship, developmental time, fecundity, oviposition and postoviposition period, and longevity of adults on date palm varieties Zahedi, Ghasb, Rabbi, Deyri and a semi-artificial diet were studied. All experiments carried out at constant temperature room (30 ± 0.5 °C and 55 ± 5% r.h.). Highest survivorship of egg and combined larval and pupal stages were 86 and 85% respectively on semi-artificial diet. Shortest total development time from egg to adult was 43 days for males and 43 days for females on semi-artificial diet. Longest total development time was 69 days for male and 65 days for female on Ghasb variety. The highest (45 eggs per female) and lowest (25 eggs per female) fecundity occurred on the Deyri variety and semi-artificial diet, respectively. Results of this study would be useful for making pest management decisions in date palm storage. Keywords : Lesser date moth, Batrachedra amydraula, Biology, Date palm

The importance of Mussidia nigrivenella Ragonot (Lepidoptera: Pyralidae) as a post-harvest pest in different storage structures in Benin

In West Africa, the most damaging lepidopteran pest of maize ears is the pyralid Mussidia nigrivenella. Although it is mostly described as a field pest, it can be found feeding on maize stored for up to 4 months. A survey was conducted in Benin in 2006 to assess M. nigrivenella infestations in different maize storage systems in the Southern (SGS) and Northern Guinea Savanna (NGS). In SGS and NGS the percentage of infested stores decreased from 86.7% to 26.7% and from 51.4% to 14.3%, respectively, during the first 28 weeks of storage. During the same time, mean numbers of M. nigrivenella per cob decreased from 0.36 to 0.04 across both zones. All larval stages, but mostly 3rd–5th instars, were frequently found even after more than 12 weeks, indicating that M. nigrivenella may have reproduced in storage, although reinfestation or delayed development could also explain this observation. The highest M. nigrivenella incidences of 16.8% and 14.4% were found in the “Ava” and crib stores, respectively. Infestations were highest in “Ava” and lowest in maize grain stored in polyethylene bags or in mud silos. In a laboratory experiment, the presence of post-harvest beetles negatively affected the bionomics of M. nigrivenella, indicating strong interspecific competition.

Postharvest management of insects in horticultural products by conventional and organic means, primarily for quarantine purposes

Purpose of review: The presence of arthropod pests in or on horticultural commodities has caused major disruptions in the storage, processing and shipment of these products. Management of these pests has posed a problem to humans for thousands of years. Current technology has led to the development of numerous means (chemical, mechanical or procedural) to control these pests. For the most part, postharvest pest control is focused on trade and exports. The accidental introduction of a pest into a place where it is not known to be present has resulted in the establishment of quarantine restrictions and export treatment requirements. This review focuses on the most current state of postharvest and quarantine treatments in development and currently in use on horticultural products. The current implementation and acceptance of these treatments is also addressed. Findings: Conventional postharvest pest control measures include treatments with chemical fumigants and topical pesticides. Concerns over environmental pollution and human health have obstructed the use of conventional chemicals and fumigants and further development of new chemicals for postharvest treatments. Irradiation is considered a conventional treatment, however, it does not use chemicals nor does it result in detectible residues in the commodity. Improvements in engineering commercial irradiators such as restricting source exposure, and the development of more powerful X-ray converters of electron beams, as well as refinement of generic treatments for groups of pests, had led to the expansion of this treatment to achieve quarantine goals. Directions for future research: Organic compliant postharvest treatments have received much attention and are the area of the most research. These treatments can include topical treatments with organic, natural pesticides and biologically derived fumigants, temperature extremes, modified atmospheres, and other novel physical treatments. The status of postharvest treatments for the control of arthropod pests both approved and in development is discussed.