JPS5822083B2 - Thinning agent - Google Patents

Description

[Detailed description of the invention] The present invention relates to chemical thinning agents.

The fruit setting habit of citrus fruits is generally cyclical, and fruit setting and fruit growth are also affected by climatic factors such as typhoons, cool summers, droughts, etc. As a result, the harvest fluctuates from year to year, making it difficult for farmers to manage their orchards. It's putting pressure on you.

As a countermeasure against this problem, fruit thinning has been carried out or attempted by hand or using chemical agents soon after the fruits have ripened.

Thinning agents for conventional varieties have been proposed, but their purpose is (1) to reduce the load on fruit trees through fruit thinning and maintain tree vigor, thereby improving the yield and quality of residual fruit, and (2) to reduce flowering in subsequent years. The main objectives are to improve the number and quality of the yield, and to extend the harvest period by growing young trees.

Recently, various varieties have been tried as fruit thinning agents for citrus fruits, but with the exception of one case, none have been put to practical use.

For example, for citrus fruits, 2,4°5-trichlorophenoxypropionic acid (2,4°5-TP), maleic hydrazide (MH), 2°4.5-)lichlorophenoxyacetic acid amide (2°4 .5-T), 2,3,6-trichlorophenylacetic acid (TPA), 3-chlorophenoxypropionic acid (3CP), α-naphthalene acetic acid (NAA)
), but chlorinated phenyl acids, chlorinated phenoxy acids, and their salts and amides have not yet been used to cause chemical damage to fruit trees (fruit cracking, defoliation, rough fruit set, and partial fruit development on the tree). It has not been put into practical use because it causes other diseases such as rotting, is highly toxic to humans and animals, and has poor fruit thinning effect.

For example, 3CP has a fruit-thinning effect on mandarin oranges in a 100 ppm solution, but it is extremely harmful.

In addition, 2,4.5-T is 20 ppm for Satsuma mandarin oranges.
The solution produces a fruit thinning effect, but at about 50 ppm, it already causes severe damage to leaves and fruits, causing keloid-like pericarp.

In the end, NAA was the only fruit thinning agent that had been put to practical use.

NAA is 200 to 30 about 30 days after citrus flowering.
Good results were obtained when sprayed on fruit trees in the form of a 0 ppm aqueous solution.

However, due to environmental pollution, chronic toxicity, and poor performance, NAA currently does not meet the registration standards of the Ministry of Agriculture, Forestry and Forestry, and its production has been discontinued.

Therefore, there is an urgent need to develop a fruit thinning agent that is better than or alternative to NAA.

An object of the present invention is to provide a chemical fruit thinning agent that is free from phytotoxicity and has a large fruit thinning effect.

The present invention relates to the improvement of the above-mentioned chlorinated phenoxy oxygen fruit thinning agent, which is 2,4-dichlorophenoxy-2'-propionic acid (hereinafter sometimes abbreviated as 2.4-DP).
The desired fruit thinning effect on citrus fruits can be achieved by using a fruit thinning agent consisting of this substance and an aqueous solution form of a fruit thinning agent containing this substance as an active ingredient.

It has been found that the fruit thinning agent of the present invention exhibits excellent effects on citrus fruits.

The cultivars that the present inventors have attempted are Citrus mandarin oranges and other citrus fruits that require fruit thinning.

The fruit thinning agent of the present invention achieved very good results.

Furthermore, phytotoxicity (
No cases of fruit drop, cracking, rough skin, or discoloration were observed.

Furthermore, the conventionally used NAA is 200 to 300 p.
Since it is ineffective unless it is used in the form of a PM aqueous solution, it will accumulate in the soil around fruit trees at a fairly high concentration, but the fruit thinning agent of the present invention only uses about 115 to 1/2 of NAA and does not cause environmental pollution. The problem of this will also be reduced.

The 2.4-DP fruit thinning agent of the present invention is dissolved in water to form an aqueous fruit thinning agent before use, and in that case, it may contain a spreading agent such as a surfactant, a stabilizer, etc. , there is no problem even if these additives are not included at all.

Furthermore, 2.4-DP is compatible with water and is stable.

As shown in the following examples, the fruit thinning agent of the present invention has 2.
It has a fruit thinning effect that is proportional to the concentration of 4-DP in the aqueous solution, so it is very advantageous in practice.

The time to apply the fruit thinning agent of the present invention to fruit trees is the time when small fruits appear after flowering of the fruit tree, and generally 20 to 40 days later is appropriate.

It has been observed that with the application of fruit thinners, small and defective fruits fall preferentially.

This can be said because the harvested fruit has better quality than hand-picked fruit.

To prepare the fruit thinning agent of the present invention in the form of an aqueous solution, it is prepared by mixing 2.4-dichlorophenoxy-27-propionic acid in water at a concentration of 25 ppm or more, preferably 50 to 100 ppm.

By spraying this aqueous solution onto the fruit trees, the amount of thinning agent applied per fruit becomes approximately constant, so the regulation of the concentration roughly corresponds to the regulation of the application rate.

That is, when spraying a fruit thinning agent onto fruit trees, the concentration ppm corresponds to the fruit thinning effect by setting the spraying limit at the point where droplets begin to drip from the tree leaves.

Of course, it should be noted that the concentration should be adjusted accordingly for fruit trees in light years (years with many fruits) and back years (years with few fruits).

The invention will now be explained in detail with reference to examples.

What you should keep in mind here is the appropriate leaf-fruit ratio for fruit trees (
For example, the number of leaves per fruit is about 20 for citrus fruits.
This is considered to be one piece.

However, the fact that fruits have light years and back years makes experiments difficult.

The experiments leading to the present invention were carried out in the late 1930s (Showa 5) for citrus fruits.
Since the experiment was carried out in 2003), an almost appropriate leaf-fruit ratio was achieved even without the use of fruit thinning agents.

However, by comparing with the conventionally used NAA and comparing with a control in which the present invention's fruit thinning agent is not sprayed, it is clear that the experimental results in the back of the year can be applied to the light year. This has been empirically clarified from the accumulation of

The next few examples show examples for citrus fruits.

Example 1 2.4-Dichlorophenoxy-2'-propionic acid was mixed with water to prepare aqueous solutions with concentrations of 25, 50, and 1100 pp.

In addition, a 200 ppm aqueous solution of NAA (α-naphthalene acetic acid) was prepared as a control.

This 200 ppm aqueous solution has been conventionally used as a standard solution.

The above aqueous solutions were applied to the test variety, a 15-year-old Ishikawa Unshu mandarin tree (Osaka Prefecture), 33 days after full bloom (June 26, 1973).
The leaves were sprayed using a sprayer until the droplets began to drip from the leaves.

The treatment was carried out by dividing each tree into branches and spraying solutions of various concentrations.

Fruit size at processing averages 1.95 cfr.
L, longitudinal diameter 1.85 crIL, average weight 4.4 g, and average leaf-fruit ratio (number of leaves per fruit) 13.6.

An investigation was conducted 40 days after the end of the menstrual period (August 5, 1978), and the results shown in Table 1 were obtained.

As can be seen from Table 1, the fruit thinning agent of the present invention produces a fruit thinning effect at 25 ppm, and achieves a fruit thinning effect equivalent to the treatment with NAA at 100 ppm.

In addition, the rate of defoliation was slight, and furthermore, no deformation or malformation of the fruit was observed.

As can be seen, the fruit thinning agent of the present invention does not cause any phytotoxicity.

In addition, the appropriate leaf-fruit ratio is already appropriate for the untreated one, but
This is due to the back of the year, and the fruit thinning agent of the present invention produces a very superior effect compared to NAA, and the fruit thinning effect is proportional to the concentration of 2,4-DP.
The superiority of the fruit thinning agent of the present invention was demonstrated.

Furthermore, from this property of the basic rule, it is easily inferred that for citrus fruits such as kumquats that require full thinning, the whole fruit thinning can be achieved by increasing the concentration of 2.4-DP as needed.

Example 2 2.4-DP aqueous solution at a concentration of 25, 50, 100°5 Three types of ppm were prepared.

These aqueous solutions were sprayed using a sprayer 28 days after the Satsuma mandarin trees (Shizuoka type) were in full bloom (June 13, 1978).

The spraying method was the same as in Example 1.

The processing method is branch-specific processing, with 1 repetition per tree and 3 repetitions (3 trees).
Shida.

When I conducted the survey on August 18th, when my menstrual period had ended, I got the results shown in Table 2.

The table shows the average of three trees. According to Table 2, the treatment with the 2.4-DP aqueous solution did not have a noticeable effect up to 50 ppm, but at 100 ppm, fruit thinning progressed and the leaf-fruit ratio increased significantly.

No drug damage was observed. Example 3 An experiment similar to Example 2 was conducted on a 12th grade Matsuyama Wenzhou mandarin tree (
Hiroshima series) was tested 30 days after full bloom.

As in Example 2, each branch is processed separately, and each tree has 4 iterations (1 iteration for each tree).
4) Shida.

Branches bearing 40 or more fruits were selected, and the thinning agent was applied in the same manner as in Example 1.

The processing date was June 268, 1978, and the survey date was August 2nd.

The results in Table 3 were obtained by averaging four replicates.

From the results in Table 3, 25-100% compared to the untreated case.
It can be seen that in the ppm range, the higher the concentration, the more fruit thinning progresses, the leaf-fruit ratio increases, and the fruit set rate decreases.

Moreover, no chemical damage to fruits and leaves was observed.

Example 4 An experiment similar to Example 2 was conducted on early-growing mandarin trees (Fukuoka Prefecture).

The treatment date was 30 days after full bloom (June 16, 1978), and the survey was conducted on August 3 of the same year.

The results shown in Table 4 were obtained. In this example, the leaf-fruit ratio is also 25.
ppm to 100 ppm, which indicates that the fruit thinning effect of the present invention is excellent.

Claims (1)

[Scope of Claims] A fruit thinning agent for citrus fruit trees, which contains 12,4-dichlorophenoxy-2'-propionic acid as an active ingredient and is used during the period when small fruits appear. Claim 1 containing 22.4-dichlorophenoxy-2'-propionic acid in a proportion of 25 ppm or more
Thinning agent for citrus fruit trees as described in section. 32. A fruit thinning agent for citrus fruit trees according to claim 2, which contains 4-dichlorophenoxy-2'-propionic acid in a proportion of 50 to 100 ppm. 4. A fruit thinning agent for citrus fruit trees according to claim 1, 2 or 3, which contains a surfactant and other additives.