Interaction of root-knot nematode and mycorrhizal fungi on common beanPhaseolus vulgaris L.

The interactions of root-knot nematode and VAM fungus on common bean plants (Phaseolus vulgaris L.), and the sequence of nematode infection were studied in the greenhouse. The inoculation with VAM fungus caused a significant increase in plant height and fresh weight compared with non treated plants.Meloidogyne infection unsignificantly decreased plant height and dry weight. When fungus was inoculated at 15 and 30 days prior toM. incognita infection, a significant increase in fresh weight was observed. There were no significant differences in total nitrogen (mg/plant) between plants inoculated withM. incognita alone or those inoculated with bothM. incognita and VAM fungus at the same time or 15 days after the fungus inoculation. Plants preinoculated with VAM fungus 30 days prior to nematode infection had a significant increase in total nitrogen. The inoculation with VAM fungus caused a significant increase in phosphorus content. However, it was significantly decreased in plants inoculated with nematode alone and in plants inoculated with VAM fungus andM. incognita at the same time. Gall index and final nematode population were significantly increased when nematodes were treated at the same time with fungus, although there were significant decrease in nematode final population and gall index when the plants were treated with nematodes at 15 and 30 days after mycorrhizal infection. A decrease in percentage of fungal colonization was observed when nematodes were inoculated with fungus at the same time.     

Potential for using Datura alba leaf extracts against two major stored grain pests, the khapra beetle Trogoderma granarium and the rice weevil Sitophillus oryzae

Various plants are well known for their insecticidal activity and their use was maintained for millennia throughout all the agricultural regions of the world. In a current context, the use of Botanical insecticides represents one of the best alternatives to chemicals for the development of environmental-friendly strategies for stored grain pest control. Datura alba Nees is a plant found extensively in the warmer regions of the world and it is used as a medicinal plant. This study aims to assess the contact toxicity and the trans-generational effect of D.?alba leaf extract (DLE) against two important insect pests on stored rice, Trogoderma granarium and Sitophilus oryzae, under laboratory conditions. Filter papers were soaked in three DLE concentration solutions and in two control treatments: water and acetone. The survivor specimens (F₀) were transferred to a new untreated feeding substrate and the population build up of the two following generations (F₁ and F₂) were counted after 30 and 60?days, respectively. The highest DLE concentration (2.5?%) induced the significantly highest mortality with 33.5 and 45?% mortality in T.?granarium and S.?oryzae after 7?days of exposure, respectively. The DLE long-term effect toward both tested species was also proved by the high demographic decrease in the F₂ generations, when compared to control groups. This study is the first step toward establishing a scientific basis for the effective application of D.?alba plant materials as biorational tools to control stored grain pests.     

Treatment of rice with diatomaceous earth and effects on the mortality of the Red flour beetle Tribolium castaneum (Herbst)

Diatomaceous earth has been demonstrated in Australia, Germany, and the USA to protect stored products from infestation by insect pests. However, application of diatomaceous earth has rarely been used in Asian countries for the protection of stored grain from insect damage. These facts and the paucity of existing data from the tropics prompted the present study of storage with diatomaceous earth. We exposed rice treated with the diatomaceous earth product Fossil Shield® to infestation by Tribolium castaneum Herbst. During the dry season, when tests were conducted, the mean temperature was 29?±?2?°C and relative humidity was 80?±?3?%. The population of T. castaneum in rice was significantly reduced after treatment with Fossil Shield®. Diatomaceous earth at 1?g and 2?g per kilogram rice reduced population growth of T. castaneum to a coefficient of 0.27, and 0.02 respectively after 42 days. Fossil Shield® at 0.5?g per kilogram rice increased the mortality of T. castaneum, but did not stop population growth.     

The use of Sesbania (Sesbania rostrata) and urea in lowland rice production in Sierra Leone

The suitability of sesbania (Sesbania rostrata) as green manure for lowland rice was evaluated in the Inland Valley Swamp (IVS) of Sierra Leone, and attempts were made to identify appropriate methods of its management in combination with urea. Sesbania — rice intercropping and sesbania — rice rotation treatments were compared with 60 kg N ha^–1 applied in two splits and 30 kg N ha^–1 as basal or top dressed to rice grown in the two cropping systems. The ¹⁵N isotope dilution technique was used to quantify N uptake from the green manure and urea and its utilization by rice. Rotating 40–50 days old sesbania two days prior to transplanting and top dressing with 30 kg N ha^–1 as urea at nine weeks after transplanting gave highest rice grain yield (121% over the control without sesbania and urea). However intercropping sesbania with rice tended to increase N uptake and N fertilizer utilization more than the rotation treatments. The higher grain yield of rice in rotation despite lower N uptake than intercropping shows that other effects than only N explain the beneficial effect of sesbania on rice.This revised version was published online in November 2005 with corrections to the Cover Date.     

Reproduction of the parasitoids Anisopteromalus calandrae (Howard) and Lariophagus distinguendus (F?rster) on arenas containing a mixed population of the coleopteran pests Sitophilus oryzae and Rhyzopertha dominica

In this article, we assessed the reproduction rates of the generalist pteromalid parasitoids Anisopteromalus calandrae and Lariophagus distinguendus on the coleopteran pest species, Sitophilus oryzae and Rhyzopertha dominica, when these hosts were offered together under environmental conditions reproducing spring or early summer. These species had proved to be the most suitable hosts in terms of parasitoid progeny production for both parasitoid species in no choice experiments in previous studies. Trials with A. calandrae and L. distinguendus had lower pest emergence in the parasitoid treatment when compared to the control for S. oryzae. However, for R. dominica, there was no difference between treatments for either parasitoid species. Pest reduction levels reached by the two parasitoids were caused by parasitism effects together with other parasitoid-induced mortality causes, which included host feeding and unsuccessful parasitism. The most preferred host under the conditions tested for both parasitoid species was S. oryzae. The parasitoid L. distinguendus decreased grain loss significantly more than A. calandrae thanks to a greater reduction of pest population. Product loss in terms of reduction of the medium (brown rice) weight was always higher in the control treatments.     

The activity of some compounds extracts byAllium on stored-product insectsOryzaephilus surinamensis (L.),Sitophilus oryzae (L.) andTribolium castaneum (Herbst)

The bioactive metabolites of someAllium plants, all exhibiting interesting pharmacological activities, were tested for their attractive/repellent activity against saw-toothed grain beetle,Oryzaephilus surinamensis (L.), rice weevil,Sitophilus oryzae (L.), and rust-red flour beetle,Tribolium castaneum (Herbst), insects infesting the stored-products. The data obtained showed significant repellent effect of the thiosulfinates againstS. oryzae. Part 6 in the series “Chemistry of the genus Allium”.     

Einsatz von Pflanzenschutzpräparaten gegen Phytonematoden zur Ertragssicherung bei Mais

Trials in maize with some granular pesticides and emulsions, which have been carried out since 1974, showed promising effects against insect pests and plant-parasitic nematodes. The infestation byPratylenchus spp. andHeterodera avenae in the roots of young treated maize plants was effectively reduced by the application of the pesticides. In trials in 1977 on 4 different localities a reduction of the nematode population by 90 per cent — in some even 98 per cent — was observed. The following pesticides were used in the experiments: Temik 10 G (aldicarb) 0.5 g/m Curaterr 5 G (carbofuran) 1.0 and 1.25 g/m Curaterr SK 30 (carbofuran) 0.15 ml/ha Counter 2 G (terbufos) 1.25 g/m Dacamox 10 g (thiofanox) 0.75 g/m. The weight of the roots of young maize plants increased after the application of the above mentioned pesticides, except after the use of Curaterr SK 30. Similar tendencies were found concerning the growth of the plants and the size of the stems of treated plants. There was also an obvious increase in yield. It could be found that there was a clear correlation between the weight of roots, the size of the stems and the weight of the grain. In 1975 and 1977 the yield of silage maize and that of grain was increased after the application of Temik 10 G and Curaterr 5 G by 10–11% compared to that of untreated plants. This means that under normal conditions of maize cultivation — at least in Hesse — and average loss of 6 dt/ha of dry matter can be caused by soil pests, mainly nematodes.     

Infleence of some organic manures as soil amendments on development and reproduction ofRotylenchulus reniformis infecting eggplant andHirschmanniella oryzae infecting rice

The effect of amended soil with rabbit, camel, poultry, quail, pigeon, horse, buffalo and duck manures to manage the rice root nematode, Hirschmanniella oryzae on Giza 171 rice plants, and effects of the first five manures in management of the reniform nematode, Rotylenchulus reniformis on Balady eggplants was studied under greenhouse conditions. All treatments significantly (p<-0.01) reduced final populations, rate of build-up and reproduction of both nematodes than in unamended soil. The reduction in such parameters greatly varied according to the type of the tested organic manure and the host plant. Generally, pigeon manure was highly effective against R. reniformis on eggplant followed by quail, poultry and rabbit manures, while camel treatment occupied the least potent manure. Consequently a corresponding statistical increase in eggplant growth resulted. As for managing H. oryzae on rice plants, buffalo dung was very potent inhibitor to its build-up followed by camel, horse, poultry, duck, quail, rabbit and pigeon manures. Percentages increase in the rice growth showed more values when applying duck and pigeon manures followed by quail, rabbit and buffalo. Horse dung improved, to some extent, the growth of rice plants although, none of the other organic manures succeeded in improving the rice plant growth. An explanation has been submitted to discuss the role of both pigeon droppings and buffalo dung on both R. reniformis on eggplant and H. oryzae on rice. This type of control of phytonematodes was considered economical, easy and pollution free.     

Host status effect of cowpea and sunflower on the populations ofMeloidogyne javanica andRotylenchulus reniformis

A highly susceptible cowpea,Vigna sinensis cv. Baladi plants were tested as trap plants for eitherMeloidogyne javanica orRotylenchulus reniformis under greenhouse conditions. The plants were gathered by cutting them above the surface of the soil or by uprooting them, 1/2, 1, 3, 6, 12, 24, 36 and 48 days after nematode inoculation. Both of the mentioned nematodes began to mature and lay eggs after the 12th day from their inoculation. Hence, it is advised to pull up cowpea plants from 3–12 days after nematode inoculation. After planting sunflower,Helianthus annus cv. Miak replacing cowpea, the nematode populations were higher, in most cases, on sunflower plants replacing cutting cowpea than those on sunflower replacing uprooted cowpea. The highest percentages of nematode reduction were 98.55 and 99.57 forM. javanica and 95.09 and 92.90% forR. reniformis on sunflower plants replacing cutting and uprooted cowpea plants after 12 days from nematode inoculation, respectively.M. javanica andR. reniformis decreased the length and weight of sunflower plants as affected by planting time and method of cowpea harvest. This method of nematode control is cheaper, easy and pollution free.     

Effects of seasonal changes on the population levels of some plant-parasitic nematodes in the plantations of Pinus caribaea and P. oocarpa in the savanna areas of Nigeria

The mean values of the total number of nematodes found in each of four pine plantations in Nigeria were depressed during the dry season to a minimum between March and April. A gradual increase in the population started from June–July, and the population reached its peak in August–October. The seasonal decline in nematode population coincided with the period of low soil moisture. An important ecological factor affecting population changes in the selected plantations was the vegetation cover; while a gradual decline in nematode population was observed in the 1968, 1974a and 1974b plantations, which have a full canopy, a sharp decline in nematode population was observed in the 1982 plot, which did not have a complete canopy. Populations of some nematode genera, such as Rotylenchus spp., Criconemella spp., Coslenchus spp. and Triversus spp., declined to zero in this last plantation.     

Male multiple matings and reproductive success in commodity-adapted strains of <Emphasis Type="Italic">Sitophilus oryzae</Emphasis>

Multiple matings occur in many species of stored-grain insect pests, such as the rice weevil Sitophilus oryzae (L.), with both female and male mating more than once and with more than one partner. Multiple female mating in S. oryzae increased lifetime fecundity by extending the period of time progeny were produced, but consequences of multiple male mating in S. oryzae were not yet studied although it is likely to increase male fitness by increasing offspring production. Here, the effects of polygynous mating on male mating behavior, success, and fitness were assessed in two strains of S. oryzae, one adapted to barley and another to wheat. Two insect strains were considered because they may differ in response depending on the host grain, which present distinct nutritional value to the insects. Mating by pairs formed between the two strains did not impact mating success, but wheat-adapted females exhibited longer mating duration, which was positively correlated with progeny production. Wheat-adapted males exhibited higher fertility than barley-adapted males. When male multiple matings were considered in successive polygynous matings, late matings led to lower non-cumulative values of progeny production, but higher cumulative performance, and wheat-adapted S. oryzae always performed better. Thus, male fitness and grain losses in wheat are higher than in barley, even when S. oryzae was adapted to the latter.     

Beziehungen zwischen der Anwendungsmethode und der Wirkung des Nematizids Nemacur gegen Meloidogyne javanica (Treub) in Tomatenwurzeln

Granular organophosphate nematicide, Nemacur 5% G was tested againstMeloidogyne javanica in tomato roots in sandy clay-loam soil at the rate of 1,5 kg a.i./feddan under three different methods of application. Results indicated that applying half of the nematicide dose two weeks pre-transplanting and the rest at transplanting time was the best method tested based on percent suppression in nematode population. Not much worse results gave the applying of all the nematicide dose simultaneously at transplanting. The effect was essential smaller when the half of the nematicide was given at transplanting time and the rest dose followed two weeks later.     

Response of tylenchulus semipenetrans to plant hormone,Giberellic acid and nematicide,Aldicarb singly and in combination

Field experiment was conducted to evaluate the efficiency of Aldicarb and Giberellic acid singly and in combination for controllingTylenchulus semipenetrans nematode, infectingCitrus sinensis var.Balady, in relation to its growth and yield Plant hormone, Giberellic acid and nematicide, Aldicarb and their combination significantly suppressedT. semipenetrans population in both soil and roots of Balady orange one and two months post application, and increased its growth and yield than that of control. The combination of Aldicarb and Giberellic acid proved good control of citrus nematode and caused subsequent increase in the growth and yield of orange tress more than the application of these chemicals alone. Yield of citrus per tree increased by up to 18.4, 17.8 and 43.6% over untreated control for treated trees with Aldicarb, Giberellic acid and their combination, respectively. The hatchability ofT. semipenetrans eggs was highly suppressed by Aldicarb and its combination with Giberellic acid. On the contrary, Giberellic acid alone did not affect the egg hatching.     

Wirkungen des Wachstumsregulators Cycocel auf Tomatensämlinge und deren Befall durch den Wurzelnematoden Meloidogyne javanica (Treub)

Cycocel, was evaluated at three different doses 500, 1,000 and 1,500 ppm achieving its effect on tomato phytotoxicity and growth in relation to root-knot nematode,Meloidogyne javanica, tomato infection. The results indicated that using 500 ppm of Cycocel was the optimum where no phytotoxic effects or reduction on plant growth were noticed at all. In addition, percentages of infected plants withM. javanica and numbers of galls per root were greatly decreased. Also, a great reduction was detected in nematode population. Increasing Cycocel concentration was parallel to the increase in phytotoxicity and decreasing of tomato growth was noticed.     

Effect of amino acids and ascorbic acid onMeloidogyne javanica Chitw. (Tylenchidae,Nematoda)

The effect of aqueous solutions of L-arginine, L-glutamic acid and ascorbic acid onMeloidogyne javanica egg hatch, juvenile survival, and maturity and fecundity of nematode females in susceptible tomato roots was investigated. All tested compounds significantly suppressed egg hatchability at all concentrations (1000, 2000 and 4000 ppm). L-arginine proved to be the best one in inhibition egg hatch and achieved the highest inhibition percentages at all tested concentration. Inhibition rate of egg hatch increased by increasing the concentration of amino acids and vitamin. L-arginine and L-glutamic acid and ascorbic acid at 2000 ppm resulted in 100% mortality ofM. javanica juveniles after 7 days exposure. Application of aqueous solutions of L-arginine, L-glutamic acid, and ascorbic acid at 1000 ppm significantly reduced numbers ofM. javanica populations, mature females and eggmasses in tomato roots. The maximum inhibitory effect was obtained by L-arginine acid which surpassed both ascorbic acid and L-glutamic acid, in reducing nematode population (R% were 84.95, 80.11 and 70.4, respectively) and in affecting maturity and fecundity of females (maturity % were 53.7, 54.2 and 67.7 and fecundity % were 39.2, 46.2 and 61.2 for L-arginine acid, ascorbic acid, and L-glutamic acid respectively, in comparison with that of control group).     

黄条金刚竹生长规律研究

从出笋、退笋、高生长规律3个方面对黄条金刚竹的生长发育规律进行了系统的观察,结果表明：黄条金刚竹的出笋历期31d左右,在出笋后第8～9d进入出笋高峰期,约占出笋总数的76．8％;退笋期主要集中在初期和末期;在前期-盛期-末期出笋所长成的竹子,其胸径和竹高均呈下降趋势;幼竹高生长呈“S”形曲线,整个过程表现出“慢-快-慢”的特点,Logistic回归方程能较好的模拟黄条金刚竹的生长过程。     

Contact and fumigant toxicity of some essential oil constituents against a grain insect pest Sitophilus oryzae and two fungi, Aspergillus westerdijkiae and Fusarium graminearum

Bioassays were performed to determine the antifungal and insecticidal activity of clove essential oil (EO), several botanical compounds (eugenol, carvacrol, allylisothiocyanate (AITC) and ethyl formate (EtF)) against mycotoxigenic fungi (Aspergillus westerdijkiae and Fusarium graminearum) and the rice weevil, Sitophilus oryzae. Antifungal activity was quantified by measuring conidia germination inhibition and mycelial growth inhibition zone to determine the minimum inhibitory concentration (MIC). Mortality of insects was determined through either contact toxicity assay (impregnated filter paper) or fumigation toxicity assay (airtight exposure chamber). A four-parameter logistic regression of fungi inhibitory growth rate to the dose of tested substances, either by the agar diffusion assay or the micro-atmosphere test, showed that AITC had antifungal and sporicide activity. The concentration at MIC for A. westerdijkiae and F. graminearum was 24.2 and 19.8???l?l^?1, respectively, whereas clove essential oil (EO) was 755 and 352???l?l^?1 after 72?h incubation period. Bioassays with S. oryzae showed that clove EO contact insecticidal activity was similar to pure eugenol and carvacrol: LD₉₀s were 366, 385 and 442???l?dm^?2, respectively. The fumigation insecticidal activity of AITC was LC₉₅?=?10.8???l?l^?1. For EtF and clove EO, only the LC₅₀ could be accurately determined after 24?h exposure time which was observed at 41 and 210???l?l^?1, respectively (vs. 6.4???l?l^?1 for AITC LC₅₀). The combined antifungal activity on mycotoxigenic seed-borne fungi and insecticidal activity against the rice weevil demonstrated that AITC in vapour phase may be a promising active substance for the preservation grain stored in unsafe conditions with a risk of fungal growth.     

Effect of space on the multiplication of the reniform nematode,Rotylenchulus reniformis Lin. & Ol. on cowpea,Vigna sinensis

The effect of space on the multiplication of the reniform nematode,Rotylenchulus reniformis on cowpea was determined under green house conditions. Both plant growth as estimated by root and shoot weights as well as its lengths and multiplication of the reniform nematode were greatly affected by the amount of space (soil). The population ofR. reniformis increased with an increase in the amount of space (soil) around seedling; highest being observed at 1,250 g of soil. The growth pattern of cowpea was attaining highest growth in 1,000 g of soil. Population ofR. reniformis increased with an increase in soil up to 1,250 g with 5 seedlings. The growth of cowpea was highest in 500 g of soil with 2 seedlings.     

Growth, physiology, and nutrient retranslocation in nitrogen-15 fertilized Quercus rubra seedlings

We evaluated gas exchange, chlorophyll index (CI) using SPAD-502 chlorophyll meter, and leaf nutritional responses in one-year-old northern red oak (Quercus rubra L.) container seedlings transplanted into control (unfertilized) or fertilized (0.86 g N plant^?1) sand culture and grown in a greenhouse for 90 days. We labeled current nitrogen (N) uptake with (¹⁵NH₄)₂SO₄ and directly quantified proportional contributions of N derived from fertilizer (NF) compared with retranslocation or N derived from plant (NP) in leaf growth of red oak seedlings. NF met a greater N demand in leaf growth of fertilized plants while unfertilized seedlings relied entirely on NP for their leaf growth. Fertilization increased leaf dry mass by 67% and new stem dry mass by 253% 90 days after transplanting compared to control seedlings. Specific leaf area (SLA) was not significantly altered but CI increased 90 days after transplanting. Higher leaf N concentration and content in fertilized compared with control seedlings was linked to greater chlorophyll concentrations in the former plants. The higher coefficient of determination (r ² = 0.72) noted between leaf N concentrations and CI suggests that the SPAD meter could be a useful tool for assessing leaf N status in northern red oak seedlings. Fertilized seedlings exhibited higher net assimilation, stomatal conductance, and transpiration rates compared with controls. Increased seedling growth in response to fertilization was related to maintenance of higher gas exchange and greater nutrient uptake, which could improve outplanting success.     

Efficacy of entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae) against the chive gnat, Bradysia odoriphaga

Chive gnat, Bradysia odoriphaga Yang & Zhang (Diptera: Sciaridae), is the most serious pest of Chinese chive, Allium tuberosum. The present study aimed at determining the biocontrol potential of different indigenous entomopathogenic nematode (EPN) isolates for the management of chive gnat in China. The virulence of 145 EPN isolates belonging to 13 species against B. odoriphaga was evaluated in the laboratory, and then the most promising isolates (Steinernema ceratophorum HQA-87; S. hebeiense JY-82; S. feltiae JY-90, JY-17; S. litorale HXY-68; Heterorhabditis indica ZZ-68; H. bacteriophora NY-63, HQ-94; and H. megidis LFS-10) were selected for further experiments. The mortality of fourth instar B. odoriphaga was significantly affected by nematode isolates and concentrations of infective juveniles (IJ). Third and fourth instars of B. odoriphaga were generally more susceptible to the nematodes than first and second instars and pupae. Pot experiments showed no differences in B. odoriphaga population reduction at 50 and 75 IJ/cm² of different isolates; the tested isolates caused a 78–94 % reduction of the chive gnat population at an application rate of 75 IJ/cm². In a field experiment, S. feltiae JY-90 generated the strongest pest suppression 14 days after EPN application, whereas after 28 days pest densities in the plots treated with S. feltiae JY-17 and S. hebeiense JY-82 were similar to those in plots treated with phoxim and yielded significant reductions of the B. odoriphaga populations. Our findings indicate that EPN may have good potential for use in the integrated management of B. odoriphaga populations in Chinese chive.