From 2000 and 2015, the organic production of spring mix lettuce increased 153% in Monterey County. Short-term lettuce data in the County reflect this trend. Since the passage of the 2012 Ag Waiver , organic head lettuce production has increased 155%, from 112 acres to 174 acres, organic romaine lettuce has increased by roughly the same percentage, from 2,750 to 4,096 acres, yet organic leaf lettuce production in the county has increased decreased slightly from 1,088 acres to 1,066 acres. An upward trend in organic production is also true for the two other crops in Monterey County for which there are longitudinal data—organic cauliflower has more than quadrupled, from 180 acres to 780 acres between 2000 and 2013, and organic strawberries production has grown exponentially, from 48 acres in 2000 to 2,082 acres in 2015. Despite the appeal of using fewer pesticides for human health, the environment and higher profit margins, a possible drawback associated with less pesticide use and/or organic production is increased pest damage resulting in crop loss. The amount of crop loss depends greatly on the pest pressure in a particular area and crop type and stage. Even within the same cropping system, pests can have varying levels of destruction.
For example,procona valencia cabbage maggots can cause yellowing, retarded growth or even plant death on brassicas , but in some propitious situations , the same brassica plants could survive cabbage maggot infestations unimpeded . The severity of pest damage can also differ within a particular region, as it does with cabbage maggot in the Salinas Valley . For example, the acceptance of pest pressure on farms could also greatly vary. The two survey responses that referenced pest damage, both from San Luis Obispo County and both who previously used diazinon demonstrate the varying degrees of frustration growers have with accepting crop loss. One respondent who previously used diazinon to control beetle populations shared his sentiments of surrendering to the pests, “We are accepting cucumber beetle damage on annual crops.” The second survey response offered a more exasperated reaction to increasing pest pressure, alluding to the fact that he wished there was alternative pesticide to use, “There is no substitute. The ants are thriving.” The two responses could be representative of varying degrees of pest pressure on two different targeted pests , different value systems, or different financial circumstances allowing one farm to accept pest pressure more readily than another. Using fewer pesticides, however, does not automatically mean a farm will experience more pest damage and lower yields . For example, a study comparing organic and conventional apple production in the Central Coast showed not only increased profits from transitioning to organic production, but also increased yields .
Additionally, a recent study in Nature found that organic farming methods promote a stronger pest control among natural enemies as well as yield larger plants than management practices typical under conventional farming systems .The costs of chlorpyrifos and diazinon also could have played a small part in some farmers abandoning their use. Clearly, data on chlorpyrifos and diazinon pricing varies substantially based on the size and cropping system of the agricultural operation and the volume discounts that large farms might receive. UC Extension, however, has estimated operating costs in their detailed Cost and Return studies, including specific material and labor costs related to insecticide use for a variety of California crops. In 2009, Smith and his colleagues at UC Extension published a Cost and Return study for leaf lettuce producers in the Central Coast region. This report estimated roughly 1 lb/acre of diazinon use on lettuce at a price of $10.45/acre. Compared to the costs of other insecticides, such as Radiant SC , or other herbicides, such as Kerb 50W , diazinon was a minor cost, and only 4% of overall insecticide expenditures . Additional costs associated with diazinon include cultural costs . In the report, these costs were estimated as an aggregate totaling $128/acre for several pest control agents, including diazinon. Weighing these costs against estimated net returns per acre is complicated by the range of farm productivity and prices received for lettuce; for example, net returns for a head lettuce farm producing 400 12-3 count cartons per acre at an average market price of $11/acre was estimated around $-2,407/acre, whereas a production of 1000 12-3 count cartons per acre at the same price was estimated to yield $111/acre in net gains.
None of the recent Cost and Return studies on broccoli in the Central Coast include estimations on chlorpyrifos use in their calculations. However, a UCE study on a related crop, cauliflower, estimates about 7.00 lb/acre of chlorpyrifos is needed for root maggot control, the target pest for both cauliflower and broccoli. The cost of the chemical was valued at $2.80/acre for a total of $19.60/acre . Compared to total operating costs for cauliflower and broccoli , expenditures on chlorpyrifos for this specific pest were relatively small . As with lettuce, net returns on broccoli vary substantially by productivity and price. A farm producing 545 boxes/acre receiving an average price of $6.80/box had an estimated net loss of $569/acre whereas a farm producing 785 boxes/acre receiving the same price was also in the red with a net loss of $112/acre. These data suggest that cost was not a persuasive factor in growers’ decision to cutback on chlorpyrifos and diazinon use. The lack of survey responses highlighting cost to be a major impetus in decision-making corroborate with these data; only one survey respondent cited the cost of diazinon and chlorpyrifos as playing a part in his decision-making to stop using them.In the Central Coast region, broccoli has historically been one of the top three crops with the heaviest use of chlorpyrifos, and lettuce is the chief crop with the highest diazinon use. The region’s year-round mild climate offers the ideal growing conditions for these cool season crops; however, the cool, wet weather is also favorable to cabbage maggots ,flower bucket the predominant target pest of chlorpyrifos on broccoli. Monterey is the leading broccoli-producing county in the state, with 40 percent of the acreage and production . The Salinas Valley, located in Monterey County is the “salad bowl of the world,” producing 80% of the salad greens consumed in the U.S.
A closer look at chlorpyrifos and diazinon application on broccoli and lettuce in Monterey compared to other regions and the state as a whole sheds light on why crop type may be a pivotal factor in allowing Central Coast growers to give up chlorpyrifos, while growers in other regions haveheld on to it for survival, and why crop type did not have as powerful an effect on diazinon’s demise.Chlorpyrifos has been one of a handful of insecticides that broccoli farmers rotate into their pest management plan to slow potential pest resistance . According to pest advisors and the UC ANR IPM program, growers tend to use chlorpyrifos on broccoli prophylactically, targeting cabbage maggots at the larval stage before the pest hatches and before it can cause damage to crops. Encouragingly, despite cutting back on chlorpyrifos, the Monterey County broccoli industry appears to be thriving. The number of acres in production and the total amount of broccoli produced continue to climb . At the same time, the market price for the crop is also on the rise, making the value per ton the highest it has been in recent years. In just over a decade, from 2000 to 2013, the value of Monterey County’s broccoli crop rose from $280.4 million to $426.9 million . These data suggest that regional broccoli growers on average are not only surviving, but thriving without the use of chlorpyrifos. As with broccoli, Monterey is the leading producer of lettuce in the state with 57% of production. Monterey and the second-lettuce producing county in the state, the Imperial County, together account for 70% of all lettuce produced in California, or roughly half of all lettuce produced in the U.S. Unlike chlorpyrifos, diazinon is used on lettuce for a variety of insect controls; and for each pest, there are a handful of readily available chemical alternatives. Consequently, the world-renowned “salad bowl” was unscathed by diazinon cutbacks. Both the production in lettuce acreage and crop totals have steadily increased in Monterey County as well as the price/value of the crop . In 2014, the most recent data available, Monterey’s lettuce crops were the highest they had ever been, valued at $1.2 billion. Comparing these same data with the second highest broccoli and lettuce-producing county in the state, the Imperial County, demonstrates that the Central Coast’s unique cool season cropping systems may be at the core of why agricultural production can thrive without chlorpyrifos, while growers in other regions are not willing or able to give it up so readily. The Imperial Valley is located in southeastern Southern California in the Colorado River Basin Region. With high summer temperatures, the Valley is well known for its number one agronomic crop, alfalfa, grossing $220 million in 2014. The region also has a reputation for its midwinter vegetable crops, including head lettuce, leaf lettuce, cauliflower, broccoli and cabbage. Alfalfagrowers in the Imperial Valley have become ever more reliant on chlorpyrifos due to the increased pest pressures from blue alfalfa aphids.
Chlorpyrifos is preferred by alfalfa growers for the suppression of these aphids over alternative insecticides, and is a fundamental tool in most growers’ IPM programs . Consequently, the region has not experienced the same downward trend in chlorpyrifos use that Monterey and the Central Coast have. Though broccoli farmers in the Imperial County were able to curtail chlorpyrifos application, alfalfa farmers in the region use a much larger share of the chemical, trumping any decline benefited by chlorpyrifos cutbacks on broccoli . Diazinon use in the Imperial Valley has declined on broccoli as well as on all crops.Fresno County, the third largest broccoli and lettuce-producing region in the state, has a parallel story to the Imperial County. Fresno County is located in the Central Valley and is characterized by its hot mediterranean climate. Taking advantage of Fresno’s ideal growing conditions as well as the lucrative almond market, farmers have been steadily converting land to almond production. In 2014, almonds were farmed on 170,711 acres up from 82,700 acres just a decade earlier. In 2013 and 2014 almonds grown in Fresno surpased the billion dollar mark, outdoing grapes for the number crop value in the county. As of 2013, almonds had the highest economic value of any California nut crop and were the highest export value of any American specialty crop .The county is the third largest producer of broccoli and lettuce in the state, and produces a variety of other vegetables including tomatoes, onions and melons. In 2013, chlorpyrifos had the greatest percentage increase in use among insecticides and most of this increase was dedicated to almond production . Almond growers became increasingly dependent on the chlorpyrifos due to budding populations of two crop pests: leaffoted bugs and navel orangeworms . Chlorpyrifos use on broccoli, on the other hand, steadily decreased as it did in Monterey and the Imperial Valley, and was trumped by use on almonds and other crops .Over the past decade, diazinon use in Fresno has declined overall as well as specifically on lettuce crops, mirroring Monterey, Imperial Valley and statewide trends. Comparing chlorpyrifos use between Monterey County, the Imperial County and Fresno County underscores the importance of crop type and pest pressure on growers decision to apply the chemical or not. This comparison leads to several interesting policy questions: Would the Imperial Valley or Fresno County have stopped using chlorpyrifos on alfalfa or almonds if it were held to Central Coast Tier 3 requirements? Or would growers have complied with Tier 3 requirements to continue producing their most profitable crops? Or, lastly, would growers have given up the alfalfa and almonds altogether to escape individual monitoring mandates? The widespread decline in chlorpyrifos use on broccoli in three different regions under three different regulatory programs gives considerable credence to other macro-conditions, besides the 2012 Ag Waiver, as causes for the pesticide’s demise. However, before jumping to this conclusion, other factors, such as differing pest pressure, must be considered.