The paper attempts to assess the extent of crop loss in rubber plantations in India, measured in terms of loss in latex and timber output and thereby to examine the comparative economics of plant protection measures against Phytophtora spp. induced abnormal leaf fall (ALF). The specific objectives were: a) to examine the extent of loss in latex and timber output in unsprayed plots vis-a-vis sprayed plots across prominent rubber clones; b) estimate the value of loss in latex and timber output across clones between sprayed and unsprayed plots; c) examine the comparative economics of plant protection measures in terms of the incremental costs and the incremental returns from sprayed plots across clones; and d) reflect upon the policy imperatives with respect to region specific Research and Development (R&D) interventions on plant protection measures in India. The study brings out significant clonal differences in loss of latex and timber output in the absence of prophylactic spraying against ALF. The observed clonal differences with respect to feasibility of plant disease control measures indicate the need for region and clone-specific recommendations for plant protection measures in India instead of the currently followed unilateral prescription with due allowance to the costs and potential benefit accrued from the control measures. The study also highlight the need for evolving interventions and agro-management/ plant protection measures for minimising the incidence of tree casualty in rubber plantation, as it amounts to loss of potential income from latex and timber from rubber plantations in India, dominated by the smallholder sector
Ability of five strains of Trichoderma pseudokoningii (antagonists) to suppress radial growth of Fusarium verticillioides (Sacc.) Nirenberg (= Fusarium moniliforme Sheldon) was examined in vitro These were T. pseudokoningii strai n1 (IMI 380933), strain 2 (IMI 380937), strain 3 (IMI 3809 39), strain 4 (IMI 380940) a nd strain 5 (IMI 380941). Each strain was paired with pathogen by inoculating at opposite ends of 9 cm petri plates using three pairing methods. Gradings were assigned to varied growth inhibition of pathogen by antagonists and analysed using GLM procedure (SAS). Growth suppression of F. verticillioides by all strains of T. pseudokoningii was significantly different (R2 = 0.98, p = 0.05) from control in all pairing methods. It differed significantly (p > 0.0003) among the strains in all pairing methods. Growth suppression also differed significantly among (p>0.0001) and within (p > 0.018) pairing methods. Growth suppression was best when antagonists were inoculated before pathogen. Suppression mechanisms include mycoparasitism and competition for space and nutrients. T. pseudokoningii strains 3 and 4 had the best (p = 0.05) growth suppression of F. verticillioides and could be used as biocontrol agents for endophytic F. verticillioides in maize plant. This experiment was conducted in the search for resedent microorganisms that might be capable of checking F. verticillioides within maize plant by competitive exclusion in subsequent experiment.
Phytophthora cambivora was isolated from the bark lesions of two 10- and 15-year-old of analysed alder trees. Additionally, Botrytis cinerea, 3 Fusarium species, Mucor spp., P. alni and Trichoderma spp. were recovered from diseased tissues. Isolates of P. cambivora from six plant species, used for inoculation of alder seedlings and plant parts, cause dthe development of necrosis. Isolate from Chamaecyparis lawsoniana was the weakest pathogen whereas those from Abies alba, Acer pennsylvanicum and Alnus glutinosa were the strongest.
Studies undertaken in 2002–2004 on ‘Golden Delicious’ apple fruits showed the presence of amino acids on the surface of their skin. Amount of total free amino acids ranged from 2.5 to 3.0 mg/L. In in vitro bioassays it was found that amino acids as a basic source of nitrogen did not activate germination of conidia of Peltaster fructicola (Johnson). However amino acids stimulated elongation of germ tubes and early hyphal growth. It was confirmed that fruit washings also contained sugars that stimulated both conidial germination and germ tube elongation. We proved also that different carbon to nitrogen proportions significantly affected P. fructicola growth. Proportions of C:N were evaluated according to newly introduced amino acid sugar index (ASI)
A nucleopolyhedrovirus isolated from the beet armyworm Spodoptera exigua (Polish laboratory culture), SeMNPV (P), morphologically similar to the viral bioinsecticide virus Spod-XR, was characterized molecularly and biologically. Phylogenetic analysis based on three conserved baculovirus genes, polh, lef-8 and pif-2, showed the highest homology of SeMNPV (P) to Mamestra brassicae (Mb) MNPV and M. configurata (Maco) MNPV, and much less to SeMNPV (Spod-XR). These findings were confirmed by genomic DNA restriction profile analyses. Bioassays revealed that SeMNPV isolated from the commercial bioinsecticide Spod-XR was themost infectious for S. exigua, while the infectivity of SeMNPV (P) and MbMNPV was significantly lower. These data suggest that SeMNPV (P) is a variant of MbMNPV.
The presented studies revealed the usefulness of spruce oil, basil oil, juniper oil and clove oil in monitoring of the occurrence of pea leafminer (Liriomyza huidobrensis Blanchard). While using above mentioned oils on yellow sticky traps, it was found that the number of trapped insects increased significantly. In relation to the control (traps without any addition of aromatic substance), the increase amounted to: 561.33%, 287.95%, 159.74% and 130.77%, respectively.
Evaluation offruits and leaves ofseventeen apple cultivars in respect of their attraction as food for caterpillars of leafroller species occurring in an experimental apple orchard was carried out over 1995 to 1998 in the Institute of Pomology and Floriculture at Skierniewice. The highest levels ofinjuries were observed on two cultivars: ‘Ligol’ and ‘Elstar’. High number ofinjured fruits was noted on the following cultivars: ‘Gala’, ‘Jonagold’, ‘Cortland’, ‘Idared’, ‘Lodel’ and ‘Szampion’. By far the number of injured fruits was lower on ‘Lobo’ and ‘Jonathan’, and the least on ‘Rubinette’, ‘Starkrimson’ and ‘Gloster’. Significant differences in the number of caterpillars settled down in leaf/flower clusters ofparticular cultivars during the vernal period were also confirmed. In each season the highest number ofcaterpillars of Pandemis heparana and Archips rosana were observed on leaves of‘Alwa’. To cultivars whose leaves were also readily settled down by the two aforementioned species were: ‘Jonathan’, ‘Cortland’, ‘Ligol’, ‘Lobo’, ‘Jonagold’ and ‘Elstar’. Relatively less caterpillars were observed on leaves of‘Arlet’, ‘Gloster’, ‘Szampion’, ‘Starkrimson’, ‘Pilot’, ‘Pinowa’ and ‘Rubinette’.
In 1993–1997 the occurrence of cabbage aphid (Brevicoryne brassicae L.) and predators from Cecidomyiidae, Coccinellidae and Chrysopidae was observed on the nine different late cabbage vegetables; Savoy cabbage cv. ‘Vertus’, white cabbage cv. ‘Amager’, red cabbage cv. ‘Langendijker’, brussel sprouts cv. ‘Maczuga’, cauliflower cv. ‘Pionier’, blue kohlrabi cv. ‘Masłowa’, white kohlrabi cv. ‘Delikates’, kale cv. ‘Zielony Kędzierzawy’ and broccoli cv. ‘Piast’. Among the examined predators only the cecidomyiid – Aphidoletes aphidimyza Rond. (Cecidomyiidae) played an important role in reducing the number of cabbage aphids. The cruciferous species had no impact on the density of A. aphidimyza population, and females laying eggs. The size of aphid colonies on cabbage leaves played the most important role.
Chemical plant protection is still an indispensable method in effective potato protection against Colorado potato beetle – CPB – (Leptinotarsa decemlineata Say) in Poland. This species is able to develop strong resistance against all active substances used in chemical and biological insecticides. The phenomenon of resistance is variable in time and in space. Therefore the objective of the study was to determine the present susceptibility level of Polish populations of CPB to main groups of insecticides recommended in Poland for CPB control.
In this paper we present the first identification of the Tomato clack ring virus isolated from zucchini with mosaic and deformation of leaves in Poland. Immunosorbent electron microscopy, ELISA test and IC-RT-PCR confirmed the identification of TBRV. RNA extracted from purified virus (size about 7.4 kb and 4.6 kb) was characteristic to this virus.
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