the fruit. Besides using an equipment prewash, it is 

 advisable to change the drench solution frequently. Since 

 disposing of the solution is a problem, minimizing the 

 voluir; of solution used in the drench equipment can 

 contribute to overall efficiency. For example, it would be 

 better to develop a system using 15 gallons of rapidly 

 recirculating drench, and change it daily, than to use a 200 

 gallon system for weeks. 



Given that you have a large volume system, the holding 

 tank should have rounded corners rather than square 

 corners. Square corners are "dead" areas, where fungicide 

 can settle out of solution. Keepingthe solution agitated and 

 the chemicals in solution is critical to maintaining proper 

 application rates. Placing rounded baffles in a square tank, 

 or using a rounded tank, can solve the problem. 



Fungicides 



There are only a few fungicides registered for posthar- 



vest use. These include the following materials: Captan 

 SOW™, Captan SOW™, Benlate 50W^, Topsin 70W™, 

 and Mertect 340- F™. Captan is only moderately effective. 

 Benlate, Topsin, and Mertect ju^e very effective, but can 

 become ineffective when fungal resistance develops. 

 Rosenberger observed that these fungicides appeared to 

 control rot better when used in combination with DPA 

 (diphenylamine) than did either the fungicides or the DPA 

 alone. When he tested the fungicides and DPA against 

 benomyl-resistant Penicillium, he discovered that DPA 

 inhibited the fungus. However, benomyl-sensitive isolates 

 of Penicillium were inhibited only marginally by DPA. 

 Most Penicillium isolates were sensitive to either DPA or 

 fungicide. Hence, in a mixed set of resistant and sensitive 

 fungal spores, such as would be expected in natural condi- 

 tions, the majority of the fungi would be affected. Interest- 

 ingly, the DPA is effective at low temperature (about 35°F) 

 but not at room temperature. 



* %t^ %t« «2^ »l# 

 wg» wg» •!• wgt 



Electric Lift Truclcs in Refrigerated Facilities 



James F. Thompson 

 University of California, Davis 



New Battery Desig ns. Although electric lift trucks cost 

 60% more than equivalently sized propane-powered Uft 

 trucks, many cold storage and precooling operations are 

 buying electric lifts for work inside refrigerated areas. One 

 reason for the switch is that new battery designs allow 

 electric lifts to operate for a full 8-hour shift in these 

 operations. But, more importantly, the savings in energy 

 and maintenance costs will more than pay for the extra cost 

 of an electric lift over its economic life. 



Energy Cost . A 5,000 pound capacity Uft truck will cost 

 $23,000 if battery-powered (this includes a charger and a 

 battery with a 6,000-hour life) . An electric lift uses electric- 

 ity for battery charging. But an electric lift produces less 

 waste heat than a propane lift, so refrigeration for remov- 

 ing lift truck heat is much less. Seven tons of refrigeration 

 capacity are needed to remove waste heat produced by a 

 propane lift, while only 2.5 tons are needed for electric lifts. 

 In addition, most of the electricity use for electric lifts is at 

 night when electric rates are often lower. 



The net effect is that electricity costs are equal for the 

 two types and total energy savings for electric compared 

 with propane are equal to the cost of propane for the 

 propane lift. To estimate propane savings, assume a 5,000 



pound lift truck uses about 1 gallon of propane per hour. 



Low Maintenance . Electric lifts have much lower 

 maintenance costs than propane lifts. Lift truck manufac- 

 turers' estimate maintenance costs for propane powered 

 trucks to be $2.50 per hour of operation, while maintenance 

 costs for electric lifts trucks are an equivalent of only $1.00 

 per hour of operation. 



For many operations, the energy and maintenance cost 

 savings of electric lifts will more than pay for the higher 

 initial and battery replacement cost of electric lift trucks. 



No Ethylene Gas No Carbon Monoxide . An impor- 

 tant added benefit of electric lifts is that they do not produce 

 ethylene gas as propane lifts do. Ethylene can cause 

 premature ripening in some crops, and postharvest disor- 

 ders such as russet-spotting in lettuce. Also, electric lifts do 

 not produce the carbon monoxide which can be a safety 

 concern if a refrigerated, enclosed facility does not have 

 adequate ventilation. 



Reprintedfrom Perishables Handling Newsletter, Coopera- 

 tive Extension, University of California. No. 62, October, 

 1987. 



* %i» %t* •]« «x* 

 •2* ^* *^ *S* 



16 



