DISCUSSION
A renewed interest in farming with more sustainable practices due to the possible risks to water quality from some dormant sprays, increasing incidents of documentation of resistance to the most commonly used insecticides, and the impending loss of traditional crop protection tools due to FQPA implementation increases the need for proven alternative pest management methodology.
The 3 regional PMA sites are an excellent demonstration that reduced risk programs using lower inputs of organophosphate and carbamate pesticides have had no more damage than the conventional methods of growing almonds, which sometimes use two or more sprays of pesticides. The 5-year continuation of the regional demonstrations created an extensive database of information about reduced risk scenarios that will be very valuable to almond growers. The monitoring performed at each site remained similar for statistical purposes, and to increase the validity of comparisons between the different almond growing regions of California, and the comparisons between crop years.
The continuation of this project for multiple years brought to light some important lessons. The primary lesson being that it is possible to produce almonds with very low chemical inputs. The data repeatedly showed that increased applications of pesticides do not necessarily correlate with better yields. However, in 2003 only, pest pressures increased in some areas, resulting in increased harvest damage in some plots that had little or no pesticide applications. This proves the critical importance of ongoing monitoring as well as the importance of adherence to accurate treatment thresholds. It is still unclear whether the increased damage in 2003 was a result of unusual weather patterns, or natural fluctuations in insect populations, or whether secondary pest pressures increase when broad-spectrum pesticides are no longer routinely applied. All of this also shows that there is still much to learn from continuation of this type of research and funding opportunities should continue to be explored.
The possibility of continuation of a closely related project brought to light the second important lesson from the almond PMA. That is, the almond growing regions of California (Northern, Central, and Southern), each have specific and differing pest pressures. Examples can be taken directly from the 3 demonstration plots. Kern and Stanislaus Counties showed high pressure from San Jose scale and mites when treatments were not applied. Also, due to lower winter rainfall in the region, Naval orangeworm control by winter sanitation requires extra effort in destroying mummies in Kern County. In Butte County, NOW control consists of removing mummies from the trees, and the higher rainfall and resident vegetation help the nut mummies to decompose without the extra steps of removing mummies from the tree rows and chopping to destroy them. Also, in Butte County, San Jose scale can be naturally controlled by beneficial insects if broad-spectrum insecticides are not applied. With this knowledge it becomes apparent that pest management guidelines for reduced risk systems must be region-specific.
The third lesson from this project is learned when an attempt is made to compare the costs of “reduced risk” pest management to “conventional” pest management. “Reduced risk” pest management can include the use of newer, more environmentally-friendly pest control materials, which are commonly more expensive than traditional pesticides. However, “reduced risk” can also include reducing inputs, meaning fewer applications or even zero. In an economic sense, the fewer trips through the orchard with the sprayer, the better. This is important to deflect the common conception that it is always more expensive to farm using “reduced risk” methods in order to reduce the detrimental impact on the environment.
It is clear the PMA has something important to offer the agricultural community. The Almond PMA has been recognized for its contribution to the decreasing reliance on pesticides to grow almonds and looked to for information about how to implement a reduced risk pest management system. This past year, the PMA received requests to share the monitoring protocols for reduced risk almond production. Although these protocols may not work for all systems, the Almond PMA has done much during the past five years to raise awareness of reduced risk farming practices among the almond growing industry, governmental regulatory agencies (such as the Environmental Protection Agency, the State Water Resources Control Board, the regional Water Quality Control Boards, and the California Department of Pesticide Regulation), as well as the general public.