Modeling the effect of stand and site characteristics on the probability of mistletoe infestation in Scots pine stands using remote sensing data

Over the past decade,the presence of mistletoe(Viscum album ssp.austriacum)in Scots pine stands has increased in many European countries.Understanding the factors that influence the occurrence of mistletoe in stands is key to making appropriate forest management decisions to limit damage and prevent the spread of mistletoe in the future.Therefore,the main objective of this study was to determine the probability of mistletoe occurrence in Scots pine stands in relation to stand-related endogenous factors such as age,top height,and stand density,as well as topographic and edaphic factors.We used unmanned aerial vehicle(UAV)imagery from 2,247 stands to detect mistletoe in Scots pine stands,while majority stand and site characteristics were calculated from airborne laser scanning(ALS)data.Information on stand age and site type from the State Forest database were also used.We found that mistletoe infestation in Scots pine stands is influenced by stand and site characteristics.We documented that the densest,tallest,and oldest stands were more susceptible to mistletoe infestation.Site type and specific microsite conditions associated with topography were also important factors driving mistletoe occurrence.In addition,climatic water balance was a significant factor in increasing the probability of mistletoe occurrence,which is important in the context of predicted temperature increases associated with climate change.Our results are important for better understanding patterns of mistletoe infestation and ecosystem functioning under climate change.In an era of climate change and technological development,the use of remote sensing methods to determine the risk of mistletoe infestation can be a very useful tool for managing forest ecosystems to maintain forest sustainability and prevent forest disturbance.

Patterns of Ips cembrae(Herr)infestation on trap and standing trees of European larch(Larix decidua Mill.)

The large larch beetle,Ips cembrae,is a significant pest causing the death of larch.In 2020,the attack density of I.cembrae on larch trap trees and standing trees was evaluated using sample sections placed along the trunk.As a defensive measure against I.cembrae,trap trees were highly effective in both spring and summer.The attack density increased with increasing trap tree surface area/volume.Galleries were established evenly throughout the entire trunk including the thin upper portion.When the number of trap trees was low and their capacity full,a continual aggregation of adults occurred due to pheromone communication,leading to attacks on healthy standing trees in the immediate vicinity.It was found that I.cembrae attacked standing trees from the trunk base,with a continual colonization of the stem up to 70%of the tree height in a time-differentiated progression of development stages.The attack density of I.cembrae on standing trees was up to 40%lower than on the trap trees.

Prevalence and Sensitization and Intestinal Parasitic Infestation of Vernal Keratoconjunctivitis in School Children of Kinshasa

Background: There is no study that estimates the prevalence of vernal keratoconjunctivitis and the association between vernal keratoconjunctivitis and intestinal parasitic infestation in our setting. Purpose: This study aimed to estimate the vernal keratoconjunctivitis prevalence, describe the profile of sensitization and determine the association between vernal keratoconjunctivitis disease and intestinal parasitic infestation in school children of Kinshasa during the scholar year from 2022 to 2023. Methods: An observational, cross-sectional study was performed from September 2022 to June 2023. The children with vernal keratoconjunctivitis were recruited by using the four-stage probability sampling technique. Children attending in the school children of Kinshasa with vernal keratoconjunctivitis were enrolled in the classroom and underwent a clinical examination and skin prick test for 11 allergens and stool examination direct with microscope in the Laboratory. Data were entered in Microsoft Sheets using SPSS version 20.0. The Chi-square test was used to compare the sex, age groups, home environment (grow trees and/or flowers around the yard), dampness in the house, keeping pets (cat and/or dog), number of people per household, number of people sharing a bedroom and intestinal parasitic infestation. The significant level was set to a value of p Results: A total of 28,800 students from four-stage probabilist sampling technique in school of Kinshasa were included, and 2100 students had symptoms according to the vernal keratoconjunctivitis-related symptom questionnaire. Children with vernal keratoconjunctivitis were enrolled and the mean age ± standard was 7.2 ± 3.7 years, with a prevalence of 7.2% and gender was three boys for one girl. All vernal keratoconjunctivitis children recruited in urban and rural part had 33.1% positive skin prick test (SPT) and 67.9% showed polysensitization. Children an urban part was more sensitized than rural respectively with Dermatophagoides pteronyssinus 28.1% vs 28.9%, p = 0.00001, Blomia tropicalis. 15.9% vs 14.9%, p = 0.00001 and cockroach 12% vs 13%, p = 0.00001 in both parts. Vernal keratoconjunctivitis children in rural part were more affected to the intestinal parasite than urban with Ascaris lumbricoides 14% vs 18.3%, p = 0.0006, followed by Ancylostoma duodenale 9.5% vs 12.5%, p = 0.003, Anguillule 7.9% vs 10.1%, p = 0.001, Oxyure 5.7% vs 8.2%, p = 0.0001 and Trichuris trichiura 2.6% vs 3.3%, p = 0.0009. Conclusion: This study outlines that the prevalence of vernal keratoconjunctivitis was 7.2% and 33.1% of children attending for vernal keratoconjunctivitis in school children had a positive skin prick test to at least one allergen, in particular for Dermatophagoides pteronyssinus, Blomia tropicalis and cockroach. The most common intestinal parasitic infestation was Ascaris lumbricoides, Ancylostoma duodenale, Anguillule and Trichuris trichiura.

Rice Grain Damage by Combination and Sequence Infestations by the Rice Leaffolder, Cnaphalocrocis medinalis Guenee(Lepidoptera: Pyralidae), and the White-Backed Rice Planthopper, Sogatella furcifera Horváth(Hemiptera: Delphacidae)

The rice leaffolder （RLF）, Cnaphalocrocis medinalis Guenée （Lepidoptera：Pyralidae）, and the white-backed rice planthopper （WBPH）, Sogatella furcifera Horváth （Hemiptera： Delphacidae）, are major insect pests in China and several other Asian countries. These two pests commonly occur simultaneously or in a temporal sequence. Thus, the investigation of the effect of complex infestations or temporal sequence infestations by these pests on rice yield has a practical signiifcance for the control of these pests. The present study comprised experiments with the following four different variables in potted rice at the tillering stage：single pest species infestation, complex infestation, complete combination infestation and temporal sequence infestation （C. medinalis infestation prior to S. furcifera and S. furcifera infestation prior to C. medinalis）. The results showed that the four infestations resulted in a signiifcant decrease in 1 000-grain weight （1 000GW） and rate of yield loss （RYL） but an increase in blighted grain rate （BGR）, with a signiifcant positive correlation with the infestation density. However, the inlfuences of the complex infestation, complete combination infestation or sequence infestation on the 1 000GW, BGR and RYL were greater than those of the single pest species infestations but did not have addition effects, i.e., the effects of the complex infestation and combination infestation or sequence infestation on the 1 000GW, BGR and RYL were less than the additive effects of the two single pest species infestations at the same densities. In the condition of the same total infestation pressure, no signiifcant differences in the 1 000GW, BGR and RYL were found between C. medinalis infestation prior to S. furcifera and S. furcifera infestation prior to C. medinalis as well as between the sequence infestation and the complex infestation.

Effects of Priming in Combination with Fungicides on Germination and Infestation of Lettuce (Lactuca sativa L.)

Two seed lots of lettuce (Lactuca sativa L.) cv. Krlowa Majowych were primed in polyethylene glycol (PEG) 8000 at -1.25MPa for 7 days in dark at 20C. Two fungicide treatments combined with PEG were used to control fungi: 1) Funaben T(0.1%) and Apron 35 SD (0.02%) were added to -1.25 MPa PEG solution (PEG+F); 2) After seed priming and drying,Funaben T was mixed at 5 g kg-1 and Apron 35 SD at 1 g kg-1 of seeds (PEG then F dust). PEG, PEG+F and PEG then F dusttreatments reduced significantly thermodormancy and increased the seed germination at 35C in both lots. PEG then Fdust treatment had the best effect on reducing seed thermodormancy at 35C, and increased seed germination to 64.5% inlot 1 and 72.0% in lot 2 compared to 0 in untreated. PEG and PEG then F dust treatments have accelerated germinationspeed at 20 and 15C in both lots. There was a significant reduction in seed infestation in which the seeds were treatedwith PEG+F and PEG then F dust compared to untreated seeds and PEG primed seeds. PEG priming enhanced seedinfestation considerably by Alternaria alternata, Penicillium spp., Rhizopus spp. and Ulocladium spp. Mycologicalanalysis showed higher frequency of Alternaria alternata and Ulocladium spp. in untreated seeds at 20C. Priming incombination with fungicides significantly alleviated the infestation of fungi, especially Alternaria alternata infestation.

Application of Laser Induced Breakdown Spectroscopy in Early Detection of Red Palm Weevil:(Rhynchophorus ferrugineus)Infestation in Date Palm

The Kingdom of Saudi Arabia is one of the leading date producing countries. Unfortunately, this important fruit crop is under great threat from the red palm weevil （RPW） （Rhynchophorus ferrugineus）, which is a highly invasive pest. Several techniques, including visual inspection, acoustic sensors, sniffer dogs, and pheromone traps have been tried to detect the early stages of a RPW infestation; however, each method has suffered certain logistical and implementation issues. We have applied laser induced breakdown spectroscopy （LIBS） for the early detection of RPW infestation. Through the analysis of the observed LIBS spectra of different infested and healthy samples, we have found presence of Ca, Mg, Na, C, K elements and OH, CN molecules. The spectra also reveal that with the population growth of the pest, the intensity of Mg and Ca atomic lines in LIBS spectra increases rapidly. Similar behavior is observed in the molecular lines of LIBS spectra. The obtained results indicate that the LIBS technique can be used for the early detection of RPW infestation without damaging the date palms.

Efficacy of aqueous leaf extracts and synthetic insecticide on pod-sucking bugs infestation of cowpea (Vigna unguiculata (L.) Walp) in the Guinea Sa-vanna Region of Nigeria

Pod-sucking bugs (PSBs) infestation by Ano-plocnemissp./ Riptortussp./Clavigrallasp./Nezaraviridula( Linnaeus) greatly limits cowpea (Vignaunguiculata (L.) Walp) production throughout sub-Saharan Africa. The efficacy of aqueous leaf extracts (ALEs) (5 percent weight/volume concentration) of three botanicals and one synthetic insecticide against PSBs infestation was thus evaluated. The botanicals tested include Aza- dirachtaindicaA. Juss, Chromolaenaodorata (L.) and Ricinuscommunis (L.), whilst the synthetic insecticide was Uppercot 500 EC ( Lambda cyhalothrin 30 g + Dimethoate 250 g ). The effects of these treatments on the number of PSBs/ pods/seeds, pod/seed weight and grain yield were assessed during 2008 and 2009 rainy seasons in Bayo, Borno State, Guinea Savanna region, Nigeria. The number of PSBs was lower on crops treated with Uppercot 500 EC (0.00 - 0.31). This was followed by crops treated with the ALEs ofA.indica/C.odorata (0.31 - 1.33) and R.communis (0.72 - 3.72) than the untreated (3.06 - 5.64) ones.The number of pods/pod weight per plant, seeds/seed weight per pod and total grain yield were generally higher on cowpea crops treated with Uppercot 500 EC (26/17 g, 14/19 g and 1618 kg). This was followed bycrops treated with the ALEs of A.indica/C.odorata (23 - 25/14 - 15 g, 12 - 13/15 g and 1268 - 1310 kg) and R.communis( 21/13 g, 11/14 g and 972 kg) than the untreated (16/9 g, 7/10 g and 312 kg) ones. Although Uppercot 500 EC was most effective inprotecting cowpea against PSBs attack, theALEs of A.indica and C.odorata appreciably protected treated crops against infestation, giving relatively high total grain yield. Both botanical scan thus serve as alternatives to synthetic insecticides for managing PSBs attack on cowpea.

Ocular leech infestation initially misdiagnosed as conjunctival pigmented nevus

Dear sir,Iam Dr.Wen-Wei Li,from the Department of Ophthalmology,Zhejiang Provincial People’s Hospital,Hangzhou,China.I write to present a case of ocular leech infestation initially misdiagnosed as conjunctival pigmented nevus.Although human interaction with leeches is not uncommon

Association of breast feeding practice with worm infestation in children aged 0-24 months in Calabar South Local Government Area

Objective:Reduction in child morbidity and mortality require improved knowledge about hygiene,baby feeding and childrearing practices,especially by mothers in low resource nations.The objectives of the study were to compare the prevalence of worm infestation between exclusively and non-exclusively breast - fed children and to determine the age at which exclusively breast - fed children child could be significantly infested with worms. Method:Systematic sampling of 196 mother-infants pairs was done.A pretested interviewer administered semi-structured questionnaire was used for data collection.Fresh stool samples collected from the children were examined using the cellophane thick faecal smear technique of Kato - Katz.Results:The difference in prevalence of worm infestation within 6 months of age was not significant between the exclusively and non-exclusively breast feed children.Age of significant worm infestation for exclusively breast -fed infants was/13 months. Mother’s educational level significantly influenced their de-worming practices.Conclusion:This study showed that breast milk does protect children in the first year of life against worm infestation;but the burden of infestation becomes significant after 12 months of age.Mothers should be taught to de - worm their children from 13 months of age.

Effects of Initial Infestation Levels of Callosobruchus maculatus (F.)(Coleoptera: Chrysomelidae) on Cowpea and Use of Nicotiana tabacum L.Aqueous Extract as Grain Protectant

This study determined the effects of initial infestation of cowpea seeds （Ife brown variety） with different insect densities （0, 2, 4 and 6 pairs per 50 g seeds） of Callosobruchus maculatus （F.） and evaluated the effects of aqueous leaf extract of Nicotiana tabacum L. on C. maculatus in the laboratory. It was observed that adult beetle population increased significantly （p〈0.05） with increase in insect density. The increase in population of beetles and corresponding weight loss of the seeds in different levels of infestation showed that the cowpea variety was susceptible to beetle infestation, emergence and survival of progeny. Significantly more adults emerged on higher infestation compared to lower and no infestation. In Nigeria, Nicotiana tabacum L. is a locally available plant, with known insecticidal properties. The plant leaf extract was easily extracted with water and confirmed its effectiveness as a protective agent for stored cowpea seeds. Experiment was conducted to assess the effects of aqueous extracts ofN. tabacum at 0, 0.1, 0.2 and 0.3 mL＂ 50 g-1 cowpea seeds on C. maculatus. Data was recorded and showed varying levels of effectiveness against C. maculatus. Result showed that seed appearance was dependent on levels of insect population, while N. tabacum aqueous extract exerted effects on survival of C. maculatus. Aqueous leaf extract of N. tabacum probably contained some insecticidal properties which might have significantly conferred beetle mortality and reduced beetle emergence leading to a decrease in seed weight loss.

Prevalence and Pattern of Intestinal Parasitic Infestations among HIV Infected Children in Lagos, Nigeria

Introduction: Intestinal parasitic infections significantly affect paediatric population globally with over 800 million children at risk. The chronic nature of these infestations is associated with chronic disabilities approaching 9 million Disability Adjusted Life Years (DALYs). Co-infection of Human Immunodeficiency Virus (HIV) and intestinal parasitic infections adorned the pre-Highly Active Antiretroviral Therapy (HAART) era resulting in impaired nutritional state and dysfunctional immune system, especially amongst affected children. The success of HAART in conjunction with other life-saving measures has improved the outcome of children living with HIV. This study aimed to evaluate the prevalence and pattern of parasitic infections among children living with HIV in Lagos. Methodology: Consecutive children attending the paediatric anti-retroviral clinic were enrolled. Socio-demographic and clinical characteristics elicited from the clinical examination were recorded. Fresh stool samples of the children were obtained and examined for intestinal parasites. Data were analyzed with the Statistics Package for Social Sciences (SPSS) 20 software. Results: A total of 102 children participated in the study with a majority being males (52.9%), in primary school (73.5%) and living in urban settings (82.4%). Six children were found to harbour intestinal parasites giving a prevalence of 5.9% with Ascaris lumbricoides (50%) and Entamoeba histolytica (33.3%) being the prevalent parasites seen. Children with a Body Mass Index (BMI) Z-score < ?1 had higher estimates of intestinal parasitic infestations [p value < 0.05, OR 10.27, CI 1.72 - 61.20]. Conclusion: The prevalence of intestinal infestation was 5.9% with Ascariasis being the commonest intestinal parasitosis in our study. Malnutrition was found to be significantly associated with its occurrence.

Morphometric Indices and Enteroparasitic Infestation of <i>Clarias gariepinus</i>(Burchell, 1822) in a Tropical Reservoir

The study was carried out using 328 Clarias gariepinus specimens over a period of two years, from Oba reservoir (08&#176;3'N to 08&#176;12'N and 004&#176;6'E to 004&#176;12'E) Ogbomoso, Oyo State, Nigeria. Standard methods were used to determine length-weight relationship, condition factor, and enteroparasitic infestation of the fish in the reservoir. Generally, Fish growth was positively allometric, while infested male and female fishes had negative allometric growth. The general well-being of the male fish was better than that of the female fish. Smaller sized fishes were better adapted to the ecological conditions of the reservoir than the bigger fishes. Parasites recovered were two Nematodes (Procamallanus laevionchus, Paracamallanus cyathopharynx), three Cestodes (Anomotaenia sp. Monobothrium sp., Polyonchobothrium clariae), and one Acanthocephalan (Neoechinorhynchus rutili). Sex ratio was 1.3:1 (male: female). Parasitic prevalence and intensity in the fish were sex and season dependent. The effect of enteroparasites in the life of infested C. gariepinus was found to probably be a major factor responsible for the low percentage of good fit to the line of regression (R2) in females. Infestation also led to loss of weight in infested fishes and this affected morphometric values in which body weight was an index.

Transcriptomic analysis reveals the defense mechanisms of citrus infested with Diaphorina citri

Huanglongbing(HLB) is a devastating disease that has led to an acute crisis for growers of citrus, one of the world's most important fruit crops. The phloem-feeding Asian citrus psyllid(ACP), Diaphorina citri, is the main pest at the new shoot stage and is the only natural vector of HLB pathogenic bacteria. Little is known about how plants perceive and defend themselves from this destructive pest. Here, we characterized changes in the expression of various genes in citrus plants that were continuously infested by D. citri for different durations(12, 24, and 48 h). A total of 5 219 differentially expressed genes(DEGs) and 643 common DEGs were identified across all time points. Several pathways related to defense were activated, such as peroxisome, alpha-linolenic acid metabolism, and phenylpropanoid and terpenoid biosynthesis, and some pathways related to growth and signal transduction were suppressed in response to D. citri infestation. The expression of genes including kinases(CML44, CIPK6, and XTH6), phytohormones(SAMT, LOX6, and NPR3), transcription factors(bHLH162, WRKY70, and WRKY40), and secondary metabolite synthesis-related genes(PAL, 4CL2, UGT74B1 and CYP82G1) was significantly altered in response to D. citri infestation. The findings of this study greatly enhance our understanding of the mechanisms underlying the defense response of citrus plants to D. citri infestation at the molecular level. Functional characterization of the candidate defense-related genes identified in this study will aid the molecular breeding of insect-resistant citrus varieties.

Infestation and morphological identification of the stalked epizoic barnacle Octolasmis on the blue crab Portunus pelagicus from the Red Sea

The intensity of infestation of the epizoic stalked barnacle Octolasmis on the blue crab was calculated for a total of 180 individuals collected around Jeddah, the western Red Sea Saudi coast. More than 90% of the crabs were found bearing the Octolasmis at a prevalence rate of 92% and mean intensity of 18.5 ? 18.6(0–127 epibiont per host). The intensity of infestation increased with host size in the range 90–135 mm. Generally, females were more infested(69%) than the males(31%). Octolasmis angulata occurred mostly on the gills, and the lower side of the gill chambers was more infested(84%) than the upper side(16%) and the left side of gills was also more infested than the right side in both males and females. Further studies are still needed to examine the commensal relationship and its impact on the fishery market of the Red Sea blue crab populations.

Association between Brainerd Diarrhea and Zebra Mussel Infestations

Brainerd Diarrhea is a syndrome of acute onset of watery, non-bloody diarrhea that lasts for a duration of 4 weeks or more. The index case of Brainerd Diarrhea was recorded in 1983, in the first such outbreak in Brainerd, Minnesota. In 1989, a prohibited invasive species named Zebra Mussels (Dreissena polymorpha) were found in the great lakes of the United States. The 7 recorded outbreaks of Brainerd diarrhea were correlated with the location and time of zebra mussel infestations. The first outbreak that occurred due to consumption of raw milk took place in Minnesota which is near the waters infested by zebra mussels. All other outbreaks were related to consumption of contaminated unchlorinated water occurred in regions not directly close to the infested rivers. However, since infestations are thought to occur due to human activity, undocumented infestations faraway are still possible. Evidence shows minor correlations between Brainerd Diarrhea outbreaks and Zebra Mussel infestations. However, none of the facts are strong enough to establish or deny a significant correlation or causation. Further cohort studies and research need to be done on the recent discoveries of Zebra Mussel infestations and new Brainerd diarrhea outbreaks. The primary search engine used to gather information for this review was ScienceDirect and PubMed. More than 35 articles and case reports were reviewed and only 20 were shortlisted and used as references. None of the studies included were restricted to study design, but studies with less than 10 participants/patients were excluded from the review.

Detecting Musk Thistle (Carduus nutans) Infestation Using a Target Recognition Algorithm

The outbreaks of invasive plant species can cause great ecological and agronomic problems through aggressively competing for environmental resources that could be otherwise utilized by other desirable species. Thus, it is crucial for detecting small infestations before they reach a significant extent that can cause ecological and economic damages over a large geological area. Remote sensing is a proven method for mapping invasion extent and pattern based on geospatial imagery and indicated great repeatability, large coverage area, and lower cost compared with traditional ground-based methods before. We investigated the feasibility and performances of adopting multispectral satellite imagery analyses for mapping infestation of musk thistle (Carduus nutans) on native grassland, crop field, and residential areas in early June using spectral angle mapper classifier. Our results showed an overall classification accuracy of 94.5%, indicating great potential of using moderate resolution multispectral satellite-based remote sensing techniques for musk thistle detection over a large spatial scale.

Resistance of Seven Biscuit Types to Infestation by Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

Seven biscuit types namely, Okin, Digestive, Cabin, Peanut, Cream crackers, Hobnobs and Glucose and wheat flour were screened for their resistance to Tribolium castaneum (Herbst) at ambient temperature of 28±2 ℃ and 78±2% relative humidity in the laboratory. 50 g of each biscuit sample were infested with four female and two male adult beetles and left for 15 days then remove for a resistant experiment and 70 days for a mortality experiment. Each treatment and the control without beetles were replicated three times. Results showed that there was significant difference (P<0.05) in the mortality rate of T. castaneum in the biscuit types and wheat flour samples, while there was no significant difference (P>0.05) in the weight loss of biscuit types. The highest adult mortality of beetles (100%) was obtained from Peanut biscuits at 28 days after infestation while there was only 5.5% adult mortality in wheat flour at 70 days after infestation. The susceptibility index was 0 for all the biscuit types since there was no adult emergence indicating that they were resistant to T. castaneum infestation. Resistance in the biscuit types could be due to chemical additives (e.g. sodium chloride and sodium bicarbonate) used in the production of biscuits, which may have inhibitory effect on the development of T. castaneum and also the low moisture content of the biscuits. Packages that can easily be perforated or damaged to allow absorption of moisture from the environment should not be used in packing biscuits.

Crab lice infestation in unilateral eyelashes and adjacent eyelids: A case report

BACKGROUND Crab lice(Phthirus pubis)infestation can occur at any age,to either males or females,and across all regions of the world.However,cases involving the eyelashes and adjacent eyelids(phthiriasis palpebrarum)are rare.Usually occurring as a sexually transmitted disease,crab lice can be spread by poor hygiene or in a dirty environment through direct contact with contaminated skin(hands)or textiles(towels and clothing).CASE SUMMARY A 50-year-old woman presented to our hospital with a 2-wk history of chronic eyelid pain and itching in the right eye,which exacerbated in the evening hours and which had not resolved following a 1-wk course of antibiotics and corticosteroid ointments(for blepharitis diagnosis from another hospital).A careful ophthalmic slit-lamp and light microscope examination revealed multiple crab lice and nits on the right upper eyelashes;the right and left lower eyelashes were normal.Following the new diagnosis of phthiriasis palpebrarum,the patient was treated by removing the affected eyelashes,the crab lice,and their nits completely.Additionally,the eyelids were washed once with povidone-iodine.A follow-up examination at 2 wk later showed complete resolution of symptoms and no evidence of re-infection.CONCLUSION This case emphasizes the importance of correct diagnosis and complete removal of eyelashes,crab lice and nits to cure phthiriasis palpebrarum.

Infestation of insect pests in tree-rice agroforestry system

The prevalence of insect pests was studied on rice BRI 1 （mukta） as understory crop grown in association with 11 years old selected tree species viz, Akashmoni. Jhau and Albida in the field laboratory of the Department of Agroforestry, Bangladesh Agricultural University （BAU）. Mymensingh during the period from July to December, 2003. Among the three species Albida and Jhau possessed the largest canopy and there light penetration rate were high. On the other hand. Akashmoni had the lowest canopy but it penetrated low amount of light. Albida-rice association showed the lowest infestation of major rice insects followed by Jhau-rice association, while Akashmoni-rice association showed the highest insect infestation. Light intensity in the control plot （absent of tree species） was maximum and it caused minimum severity of insects infestation as compared to other associations. From the result it appeared that light interception has the relationship with insect population in rice. Therefore, tree species having sparse canopy which allowed easy penetration of sunlight is suitable for tree-flee agroforestry system.

Influence of Whitefly, Bemisia tabaci （Gennadius）, Infestation on Micronutrients Content in Some Vegetable Plants in a Greenhouse

The whitefly is well-known as a serious pest on many economic vegetable crops. It feeds by absorbing plant sap which includes many important nutrients for plant,＇;. An experiment was carried out to investigate the effect of whitefly, B. tabaci （Gennadius）, infestation on the micronutrients; Manganese, Zinc, Copper and Molybdenum, in three plant varieties; cantaloupe （Cucumis melo L.）, cucumber （Cucumis sativus L.） and zucchini （Cucurbita pepo L.） that were planted in a greenhouse at the Agricultural Research Station in Hada AI Sham, north east of Jeddah in Saudi Arabia. Results of this investigation showed that, in general whitefly infestation reduced micronutrients content in plants. Mean content of total micronutrients in each of infested cucumber and zucchini were less than control plants significantly, but the infestation did not vary total micronutrients content in cantaloupe significantly. Feeding of the whitefly reduced mean content of each Zinc and Molybdenum in infested plants significantly, but did not vary Manganese and Copper content significantly.