The Role of Forecasting in Crop Protection Decision Making: an Economic Viewpoint1

In making crop protection decisions, farmers have to answer two questions: what type of control measure(s) should I adopt? How should I apply this (these) measure (s), when, how frequently, etc.? The answer to these questions will depend upon: a) the dimensions of pest attack and the damage it causes, b) farmers' goals, c) the range of protection measures available to them which they can use, and d) the information available, in the form of monitored and forecast information. It is within this context that the role of forecasting is considered. An analysis is made of the possible impact that forecast infomation can have on farmer decision-making, particularly with regard to the accuracy of the forecast and the time at which it is available. This leads on to the problem of assessing the value of a forecast at a regional level, against which the costs of providing such information can be set. Finally, situations in which forecast information is likely to be of greatest value (and of least value) are identified, and implications are drawn concerning the institutional and other changes that could be taken to allow better use to be made of forecast information. Lorsque les agriculteurs decident de proteger leurs cultures, ils doivent repondre aux deux questions suivantes: quel est le mode d'intervention a choisir et comment, quand et a frequence faut-il intervenir. La reponse dependra notamment: de I'etendue de I'infestation et de L'importance des deglts; des buts que s'est assignes L'arboriculteur; de la gamme de methodes dont il dispose; des previsions qui lui sont fournies. La prevision est condideree dans ce cadre, puisqu'elle est susceptible d'infuler sur les decisions de L'agriculteur dans la mesure ou elle est etablie avec precision et au bon moment. I1 est donc utile d'evaluer L'inter6t economique d'une prevision regionale en faisant intervenir le cofit de celle-ci. Enfin, il est fait etat de situations dans lesquelles la prevision est profitable ou non. Suivant les cas, certaines modifications structurelles peuvent s'imposer afin de mieux tirer benefice des previsions.     

Bilateral nasolacrimal duct atresia in a cria

A 2-month-old, male alpaca had a 1-month history of mucoid ocular discharge from the left eye. Signalment, history and clinical findings were suggestive of a congenital nasolacrimal outflow obstruction. A dacryocystorhinogram confirmed bilateral nasolacrimal duct atresia, which involved the distal half of both nasolacrimal ducts. In order to establish alternative outflow, a conjunctivomaxillosinusotomy and conjunctivorhinostomy were performed on the right and left eye, respectively. The surgical openings remain patent after 11 months, and there have been no clinical signs of nasolacrimal disease.     

Effects of protein engineering of canola procruciferin on its physicochemical and functional properties

The primary structure of Brassica napus procruciferin 2/3a was engineered to elucidate structure-function relationships and to improve the functionality of cruciferin. The following mutants were constructed: (1) C287T, (2) DeltaII, variable region II was deleted; (3) C287T/DeltaII, mutation involving (1) and (2); (4) DeltaIV + A1aIV; and (5) DeltaIV + A3IV, variable region IV was replaced with variable region IV containing many charged residues from soybean glycinin A1aB1b and A3B4 subunits. Differential scanning calorimetry analysis revealed that the A1aIV region has a more favorable interaction with the procruciferin molecule than does A3IV as well as the original regions. On the basis of heat-induced precipitation analysis, it was concluded that replacement of the free cysteine residue with threonine (C287T) and insertion of charged regions (DeltaIV + A1aIV and DeltaIV + A3IV) could lead procruciferin to form soluble aggregates after heating. Low solubility was observed in mutants DeltaIV + A3IV, DeltaII, and C287T/DeltaII, especially between pH 4 and 6 at mu = 0.08, but not in DeltaIV + A1aIV, indicating that the number of acidic amino acid residues and the high number of glutamine residues are important factors for solubility at mu = 0.08. None of the mutants showed any improvements in emulsifying ability, indicating that destabilization and addition of the hydrophilic region are not effective for emulsification. The insertion of the A1aIV region in procruciferin made the molecule more susceptible to alpha-chymotrypsin.     

Use of electrospray mass spectrometry for mass determination of grape (Vitis vinifera) juice pathogenesis-related proteins: a potential tool for varietal differentiation

Methods based on liquid chromatography-mass spectrometry (LC-MS) and protein trap mass spectrometry (trap-MS) were developed to determine the complement of pathogenesis-related (PR) proteins in grape juice. Trap-MS was superior to LC-MS in terms of simplicity, rapidity, and sensitivity. Proteins with a wide range of masses (13--33 kDa) were found in the juices of 19 different varieties of grape (Vitis vinifera) and were identified as mostly PR-5 type (thaumatin-like) and PR-3 type (chitinases) proteins. Although the PR proteins in juices of grapes are highly conserved, small consistent differences in molecular masses were noted when otherwise identical proteins were compared from different varieties. These differences persisted through different harvest years and in fruits grown in different Australian locations. With the definition of four different masses for PR-5 proteins (range = 21,239--21,272 Da) and nine different masses of PR-3 proteins (range = 25,330--25,631 Da) and using statistical analysis, the methods developed could be used for varietal differentiation of grapes grown in several South Australian locations on the basis of the PR protein composition of the juice. It remains to be seen whether this technology can be extended to grapes grown worldwide and to wine and other fruit-derived products to assist with label integrity to the benefit of consumers.     

Magnesium influence on plant uptake of phosphorus in a calcareous soil

A pot experiment was conducted to investigate the role of magnesium (Mg) in plant utilization of ³²phoshorus (P)‐labelled P in a calcareous soil (Typic Hapluquent). Results with two successive harvests of ryegrass shoots indicated that Mg had no obvious influence on plant uptake of the P applied. In a separate incubation study with the same soil, labelled P along with different levels of Mg was introduced to the soil at two time intervals and soil inorganic P was fractionated. The isotope data of P in various fractions indicated that Mg at the test levels had no obvious influence on P transformation either. It is suggested from the experiments that Mg is unlikely to be able to promote plant utilization of fertilizer P in calcareous soils.     

Acetyl-CoA carboxylase of sheep adipose tissue: problems of the assay and adaptation during fetal development

The rate of fatty acid synthesis of perirenal adipose tissue of fetal lambs decreased by 90% during the last month of gestation. There was also a 90% decrease in the activity of fatty acid synthetase during this period, but the activity of this enzyme exceeded lipogenic flux by a factor of 10. The activity of acetyl CoA carboxylase in the active state (initial activity) was very similar to the lipogenic flux in adipose tissue from lambs at 120 d of gestation; although activity decreased towards term, the decline was insufficient to account for the fall in rate of fatty acid synthesis. The study also shows that assay of acetyl CoA carboxylase in the active state of ovine adipose tissue and of caprine mammary gland requires the presence of citrate, thus differing from that for rat adipose tissue. Evidence that pyruvate carboxylase can interfere in the assay of acetyl CoA carboxylase also is presented.     

Evidence of estrogen receptors in normal human osteoblast-like cells

In seven strains of cultured normal human osteoblast-like cells, a mean of 1615 molecules of tritium-labeled 17 beta-estradiol per cell nucleus could be bound to specific nuclear sites. The nuclear binding of the labeled steroid was temperature-dependent, steroid-specific, saturable, and cell type-specific. These are characteristics of biologically active estrogen receptors. Pretreatment with 10 nanomolar estradiol in vitro increased the specific nuclear binding of progesterone in four of six cell strains, indicating an induction of functional progesterone receptors. RNA blot analysis demonstrated the presence of messenger RNA for the human estrogen receptor. The data suggest that estrogen acts directly on human bone cells through a classical estrogen receptor-mediated mechanism.     

Carbon flux and growth in mature deciduous forest trees exposed to elevated CO2

Whether rising atmospheric carbon dioxide (CO2) concentrations will cause forests to grow faster and store more carbon is an open question. Using free air CO2 release in combination with a canopy crane, we found an immediate and sustained enhancement of carbon flux through 35-meter-tall temperate forest trees when exposed to elevated CO2. However, there was no overall stimulation in stem growth and leaf litter production after 4 years. Photosynthetic capacity was not reduced, leaf chemistry changes were minor, and tree species differed in their responses. Although growing vigorously, these trees did not accrete more biomass carbon in stems in response to elevated CO2, thus challenging projections of growth responses derived from tests with smaller trees.