Pear tree

A unique problem in pear trees is the pear psylla, a sapsucking insect that deposits sticky honeydew, which supports the growth of black sooty mold. Spray psylla with Insecticidal soap. The next season, spray with horticultural oil In early spring and again when buds show green. 

Pear psylla Tiny insects called pear psylla suck juice from pear trees and release honeydew that supports the growth of black sooty mold. 

Decline Oxytetracyc- -line transfusion pear trees... 

Drukker, B., Scutareanu, P. and Sabelis, M. W. (1995). Do anthocorid predators respond to synomones from Psylla-infested pear trees under field conditions. Entomologia Experimentalis et Applicata 77 193-203. 

Phloridzin, a toxic glycoside from the bark of the pear tree, blocks the normal reabsorption of glucose from the kidney tubule, thus causing blood glucose to be almost completely excreted in the urine. In an experiment, rats fed phloridzin... 

WUfrr of WDotully. Pomegranate, 1-35 Ebony,, 1 83 Dutch. Boxwood. 1-82 Heart of Oak—sixty years old 1-17 Medlar, 0-94 Olive 0-92 French Bon wood 0-91 Spanish Mulberry,.,., 0 89 YsrtOtjofWfxri DttiBlfi/. Maple, 0-75 Cherry-tree 0-78 Orange-tree. 0-70 Elm—the trunk - 0-67 French Walnut 0-67 Pear-tree. 0-68 Spanish Cypress, O 04 Lime-tree 0-00 Hazel, 0-60 Willow 0 58... 

Raese, J.T. (1990). Importance of weed control and nitrogen fertilizer on growth and yield of young bearing apple and pear trees. J. Sustain. Agric., 1 7-18. 

For optimum fruit quality, almost all pear varieties need a warm site, rather similar to that required for wine grapes. If these conditions are not present, the fruit very often does not have the desired melting texture and has little flavour in extreme cases the fruit may taste carroty . This applies particularly to late-ripening cultivars. Pear trees are somewhat more sensitive to winter frost than apple trees, and are at severe risk from late frosts because flowering is about 10 days earlier. 

In spring the fungus first attacks the juniper bush. In wet weather the spore deposits on the juniper trees can swell up and get on to the pear tree leaves, where they penetrate and produce orange-red patches on the top after 3-4 weeks. The spore deposits are formed on the underside of the leaf. These spores return to the juniper trees, where the pathogen overwinters. 

The only control measure which has been found effective is to remove all juniper bushes within a radius of 30-50 metres from the pear trees. 

The pear sucker is a pest which attacks the tips of shoots. Any measures which can check the growth of pear trees have a positive effect on infestation by pear suckers in the second and third generation. 

In small orchards, you can take the time to protect individual fruit on apple and pear trees by enclosing them in paper bags. The bags prevent insect pests from finding and damaging the fruit. 

H 5.92%, O 41.14%. From dried leaves of Bergenia crassi/blia (L.) Fritsch, Saxifragaceae Tschitschibabin et at., Ann. 479, 303 (1930) from leaves of blneheTry, cranberry, and pear trees (Pyrus communis L., Rosaceae) Urban,... 

Norland, R.H. 1976. What sinaMusbroom. Pear Tree Publications, Ashland, or. 

Isolations of noformycin (10) [25] with antiviral activity [26] and an inhibitory effect towards inducible-nitric oxide synthase [27] and other iminopyrroglutamic acid derivatives 11-13 have also been reported. The latter were inhibitors towards Erwinia amylovora, a bacterium responsible for the fire light disease of apple and pear trees [28] (Figure 10.3). 

CbHuOj, Mr 250.25, [a +6.7° (CHCI3). A ]3-lactone from Pseudomonas syringae p v. papulans. P. is weakly cytotoxic (2-6 mg/mL show chlorotic activity while 1 mg/mL does not) and is possibly responsible for various diseases of apple and pear trees ( apple blister spots ). In addition to P. the biogenetically related methyl esters of 3-phenyllactic acid bearing hydroxy and nitro substituents on the phenyl ring are also formed. Further a-oxetanones are, e.g., ebelactones, esterastin, obafluorin, lipstatin, tetrahydrolipstatin, and valilactone. 

Arbutin occurs in leaves of the pear tree Pyrus communis) and Arctostaphylos uva-ursi, and is a urinary tract antiseptic and diuretic. Arbutin is hydrolysed to hydroquinone in alkaline urine, this effect being strictly localised in the urinary tract. It is indicated for urinary tract infections, in particular cystitis, urethritis and prostatitis. 

Examples of simple phenols (Ce) include catechol and phloroglucinol. Although most of the more complex plant polyphenols contain these two simple phenols as a parts of their stracmres, catechol and phloroglucinol are uncommon in plant tissues. Catechol has been found in leaves of Gaultheria species, while phloroglucinol has been found as glucoside in the peel of various Citrus fruits. Arbutin (III) is found in leaves of various Vaccinium spp., such as bluebeny, cranberry, cowberry, and pear trees (Pyrus communis L., Rosaceae) [41-43]. 

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